Hi, Sweetpea.

Hi Mummy Bear

 Another Chit Chat.

 It is. We have episode 81 of Chit Chats.

 That’s right. And this time it’s with Kevin Martin.

 Yes.

 And Kevin is head of tree collections at Kew. He was on Gardeners’ World 2026 episode 8,

 when he joined Eliot Barden at Majestic Trees to talk about the native versus non-native

 trees.

 Exactly.

 Especially in our changing climate. And they were prepping for Chelsea,

 because one of the big things that they’re trying to do is to get us, the general public,

 on board with what new trees we need to be considering as our temperatures continue to

 increase in the summers and we continue to get wetter winters going forward.

 Exactly.

 And we talk a lot more about that. And it is a truly fascinating subject.

 And we find out that Kevin is currently working on his PhD in

 Provenance Selection of Urban Trees Under Climate Change Scenarios,

 which makes him very much the right man for this job of answering Sweetpea & bear’s

 questions about trees.

 Exactly. And also a very long PhD to have to tell everyone about.

 They’re all long titles, but all joking aside, we were really, really,

 really chuffed to have Kevin on board. So thank you so much for your time, Kevin.

 We relied quite heavily on Professor Google through this Chit Chat, because

 throughout Kevin would rattle off long Latin names of trees. I’m not very good on my trees.

 We very much needed Google to be involved. But so interesting the breadth of knowledge

 he has on all things trees. So we’ve learned a heck of a lot, didn’t we?

 Yeah, it was really, really, really great because then there were a few more

 Gardeners’ ‘World shows that came up later and they talked about trees and I was like,

 boom, we talked about this with Kevin.

 Kevin told me about that.

 Thank you.

 Well, as always, we have links on our website to a lot of what we talked about, such as

 Kevin talks about a satellite image of the UK during the heat waves during the drought,

 where you can very clearly see a line between the southeast and the northwest of the country.

 Yeah, a line of green and brown.

 Yeah, green and brown. So I’ve included that image on our website.

 Also, some of the people he’s working with, such as Dr. Andrew Hirons,

 Alex Summers he mentions, Dr. Debbie Hemming. So linked to all of them.

 Also linked to the book that he mentions was written by Arit Anderson and Henrik Sjöman. So that’s all included as well. And then also Kew’s Landscape Succession Plan

 that he mentions. So you can find all of those on our website. And then also there are

 some recommendations from Kevin, where to get your trees from, for example.

 Which is a must, must have.

 It’s a must have.

You have to have these because we need to prepare people.

 We need to prepare people. We need to have more trees, really. I think

 one could summarize the whole chat in we need more trees.

 We need more trees. Yeah, exactly.

 And the right trees, of course.

 Precisely.

 So for all of those links, head over to our website, notjustagarden.co.uk,

 click on Podcasts, then Chit Chats, Kevin’s face.

 Whack it in there.

 You’ve got it all there.

 In terms of noises, there was a truck reversing up quite a lot at Kevin’s end.

 Something going on there with a lot of trucks.

 Trees. Trees on trucks.

 Just trucks, really.

 Trees on trucks.

 And creaky chairs.

 Yeah. But tell us the format.

 So for Kevin’s Dream Garden, we have Garden Boundaries,

 Shed or Greenhouse, Five Ornamentals, Five Edibles,

 One Statement Tree, Pond or Pool plus one plant,

 and finally, Favourite Seating Area, Drink and One plant for that area.

 And if you have any questions or comments on anything we’ve chatted about,

 please do get in touch either through the contacts page on the website at

 notjustagarden.co.uk

 or through our new email address which is

 hello@notjustagarden.co.uk

 Right, we should jump into this one then.

 I think we should.

 This is episode 81, A Good Old Chit Chat with Kevin Martin.

 Off we go.

 Welcome, Kevin, to A Good Old Chit Chat.

 Thank you for inviting me along.

 Thank you for joining us.

 You were on Gardeners’ World a bit earlier on this year on episode 8

 when you were chatting to Eliot Barden, I think, weren’t you,

 and you were talking all about trees.

 Yeah, so I was up at Majestics and we were looking at tree selection

 and looking at their Chelsea stand

 and they were looking at how we could select trees for the future.

 And Eliot was a student here at Kew, so that’s how I know Eliot.

 He actually spent six months in my team, in the tree team,

 and that’s where I got to know Eliot when he was a Kew Diploma student.

 Yeah, well, so he was selecting trees for their stand at Chelsea

 and the theme that they were going with specifically

 was resilient trees for the future, wasn’t it,

 and those that can adapt for climate change.

 And you were talking, both of you were talking about

 how we look at native trees

 of which we’ve got around 30 to 35 options there.

 We have to broaden our horizons and consider the thousands of,

 literally thousands, so you said, I think you said,

 3,500, 4,000 trees that we can select from exotics.

 Yeah, so it’s really interesting.

 So with the work that I do, so just so you listeners know,

 I’m doing a PhD at Lancaster University

 and basically my research is built around

 how we look at urban trees, but more importantly,

 what trees we select under climate change scenarios.

 So we look at various different ways

 that trees have plasticity or the ability to adapt

 to like what we’re going through now.

 Like this summer that we’re going through

 with these long, hot, dry periods without any rain

 or little rain is gonna become more normal

 by the end of the century.

 So we really have to think now about what we plant

 because any tree we plant today is only gonna be

 a young adult when this is gonna become more normal.

 So it’s really understanding the real impact

 that this human influenced climate change is having,

 especially on trees because they’re long lived species

 and how we can now try to understand

 what trees we select so they have a better chance

 of being able to adapt to these conditions.

 So you mentioned there what we’re,

 the climate change that we’re feeling already.

 I saw a video of yours that in 2022,

 you lost 460 trees at Kew and that was 2022.

 We’ve had numerous heat waves already in 2026.

 What temperatures are you looking at

 at the moment in July of 2026?

 Yes.

 So we’ve had a number of days of mid 30 degrees.

 As humans, we experience heat.

 So that’s how we relate to trees.

 When we look at what the Met Office did

 and the Met Office released those red warnings,

 that’s because we had heat combined with humidity.

 Now for humans, that’s really bad

 because we can’t sweat and cool down.

 For trees, that’s actually really good

 because that humid air then reduces

 the amount of moisture loss from the system.

 So what we do is we look at something

 called vapour pressure deficit.

 That’s the dryness of the air.

 And what we see is when we have a fine breeze,

 so a gentle breeze and then high heat

 that dries out the air really quickly.

 That’s what we’re seeing becoming more common

 because we’ve had no rain.

 So we’ve got no moisture in the landscape.

 That then drives the water demand in the plant.

 So what will happen is that extra pool for that moisture,

 the tree will then need the water resources

 to keep up with that pool.

 So lots of water.

 So it can keep up with that trans-respiration pool.

 Or as we are now and we’re in drought conditions,

 what will happen is the hydraulic system

 starts to break down.

 So what we will get is an embolism

 within the Zion vessel.

 Now the best way to think of that,

 if you have a central heating system

 and you have air in the radiator,

 you have a really warm bottom of the radiator

 but really cold top.

 That’s what happens inside a tree.

 However, in your heating system,

 we let the valve out and we let the air out

 and then the water recirculates

 and you have warming of the radiator.

 Unfortunately for trees,

 they don’t have the ability

 to have a pressure relief valve.

 So what happens is that vessel then becomes dead.

 That vessel dies.

 So as this carries on,

 what will happen is more and more water

 leaves the system.

 So more and more vessels then become cavitized

 and then that’s what causes death

 or mortality in trees.

 So when you start seeing them wilt

 and that wilting point and everything

 starts to collapse,

 that’s because there’s no water

 in the Zion vessel.

 It’s just full of air and then that collapses.

 And that’s when we start to see trees

 unfortunately die in these heat,

 in these big high dry environments.

 That’s what we’re trying to understand.

 So in research…

 Can I just ask?

 So when it wilts,

 is that then past the point of no return?

 There’s nothing you’re going to be able

 to do with the wilted tree after that point.

 Oh, that’s very sad.

 It’s not like, say, a salvia which wilts.

 No, no, this is a different wilt.

 Yeah, it’s a completely different one

 because they have so much stored energy

 in order to deal with it.

 But when that cavitation,

 all those vessels become cavatized.

 It can’t pour any water.

 It’s completely hydraulically locked.

 And that’s when we start seeing

 mortality in the landscape.

 And it’s really hard

 to try to explain to people

 that it’s not just heat

 and it’s this humidity

 and it’s the whole system.

 It’s actually quite complex.

 So when you look at it,

 so in our own gardens,

 in our back gardens,

 you can try to mitigate that by irrigating,

 but it’s how much you irrigate

 and at what time and what species.

 And you’ve got to remember,

 this is what I find really intriguing

 is the Great British Garden

 has always been designed around,

 especially China and Japan,

 because that’s where

 the first plant collectors went.

 So if we think of our gardens,

 they’re magnolias,

 they’re cherries,

 they’re rhododendrons,

 they’re camellias

 and they’re Japanese maples

 because they’re really colourful.

 Now, the reason why they’re so colourful

 and have amazing flowers

 is because they come from an environment

 where they have more resources

 than what they need.

 So that allows them

 to have big show of flowers

 because in nature,

 they don’t have to invest

 into hydraulic safety.

 They can go for growth and show off.

 Now, in the UK,

 in the Victorian era,

 right up to about the early 2000s,

 we was having enough moisture

 within our system

 to support those plants.

 But what we’ve seen

 for the last decade

 and what we’re seeing now,

 the transitional period we’re in now,

 when we look at climate models,

 which is what I used to do my research,

 we can see we’re in this acceleration point.

 So what’s happening is

 we’re accelerating

 from a moist temperate ecosystem

 and we’re transitioning into semi-arid.

 Now, we’re in that acceleration point.

 So culturally,

 when we think of horticulture,

 especially ornamental horticulture,

 we haven’t caught up.

 So we’re still trying

 to plant these really show off plants.

 But our system in the southeast

 doesn’t have that support network

 to support those show off plants.

 Now, what’s really interesting is,

 I give lots of evidence in government

 and other environmental committees,

 is that we want a one rule fits all.

 But the UK is becoming so split.

 So if we look at the southeast

 and how dry we are on the southeast,

 it’s just completely different

 in the northwest.

 Because if you look at

 what’s happening in the northwest,

 when my brother lives in northwest Scotland,

 they’re still having lots of rain

 and they’ve hardly had any sunshine.

 Whereas us in the southeast,

 we’re really struggling.

 Couldn’t be drier.

 It couldn’t be drier.

 So you need a massive hose,

 is what you’re saying.

 Exactly.

 But it’s really if you look,

 BBC early this week

 released a satellite image of the UK

 and you can see that split environment.

 So from Birmingham to the southeastern east is dry

 and you see it’s all brown.

 And then from Birmingham going northwest

 all the way up, it’s green.

 And it’s really interesting.

 Yeah.

 Well, we did a big research project

 and we looked at 22 cities across the whole UK

 and we looked at 18 most sold species

 from a nursery.

 Glasgow, you can grow any tree.

 Wow, that is really the place to be, isn’t it?

 Yeah, that is the perfect point now

 for climatic conditions in 2100 is Glasgow.

 Well, so that answers one of my questions I had

 because I saw in a post you put on Instagram,

 you had given a talk

 and somebody commented and said,

 glad everyone was clear the results apply to London

 and should not be extrapolated

 to the rest of the country

 where climate change is affecting different regions

 in different ways.

 So that’s precisely what you’re talking about there.

 So we’re talking, well, so just jumping back,

 so many questions around this

 and it’s going to be hard to sort of keep it

 in a coherent linear route.

 But earlier you said about irrigating

 the right amount at the right time

 for the right trees.

 So then obviously you’ve got the variable

 in terms of what tree it is,

 you’ve got the variable

 in terms of what part of the country you’re in.

 If you were looking at Kew, for example,

 and you are dealing with death of 460 trees in 2022,

 summer’s only getting hotter and drier.

 What are you doing to mitigate these changes

 when it comes to irrigation?

 Yes, so it’s really interesting.

 I’m working on a project with the Met Office.

 I do a lot with Dr. Debbie Hemming

 who is in charge of the climate change

 and adaptation team for vegetation

 in the Met Office.

 And we’re looking at creating digital twins.

 So how we build this out is we use soil sensors.

 So we’ve got soil sensors throughout the gardens.

 So I’m monitoring moisture constantly.

 These probes go down to a meter.

 So we’ve got a full soil probe.

 So how many of those are you putting around?

 And we’ve got five there.

 We’ve got six there.

 We’ve got about 10 to 12 sensors out

 in various different locations in the Arboretum.

 Unfortunately for us, Kew is very boring as a soil.

 It’s sand over gravel.

 That’s it.

 So we’ve got no water holding capacity within our soils.

 So your soil type makes a big difference.

 Whereas at Wakehurst, our rural botanic garden,

 they’ve got a lot of clay in topsoil.

 So it’s very different there.

 But what we see here is with the sand

 and the free draining nature of our soils,

 we can’t hold our moisture.

 So watching it move through the soil is really important.

 So what we’re now doing is we’re measuring

 how much irrigation we put out

 through our irrigation system.

 Which at the moment is potable water, drinking water.

 So we’re irrigating.

 We can measure the amount of moisture within the soil.

 And then we use things like stomatal conductance,

 which is the way that we can measure a plant

 before we can visibly see it goes into drought stress.

 We can pick that up.

 So what we’re doing is trying to understand

 that what soil moisture we need to be at

 before that plant goes into stress.

 Because if we can just manage that moisture

 and then we know when plants go into stress,

 we can then manage our irrigation.

 Now that would allow us to create a digital twin.

 So we could then go, right,

 the full weather forecast is saying

 we’re gonna have X amount of rain for six weeks.

 This is how much irrigation we need to use.

 Now, once we understand the volume of irrigation,

 we can then look at rainwater harvesting.

 So we can look at our lakes

 and the underground tanks that we have

 and other rainwater harvesting methodologies

 that we’re gonna implement to then hold rainwater

 so we can then use that to irrigate the landscape.

 Because we’re gonna be in a really difficult situation.

 By 2050, we’re gonna struggle

 to have enough reservoir capacity

 to support drinking water alone in London.

 Because we’re not getting enough rainfall to replace it.

 So we’re really gonna have to start understanding

 how we manage landscapes

 because watering plants is gonna become very difficult by 2050.

 So we’re already in hosepipe bands.

 So these are the things we’ve got to manage

 as gardeners going forward.

 So at Kew, we’re trying to keep in front of the curve

 as best we can by using research

 and being partnered with people like the Met Office

 so we can understand how to manage that.

 So for us, we need to look at irrigation and how we irrigate.

 So a lot of us in our gardens,

 we use overhead irrigation, so sprinklers.

 That’s not the best use of it.

 So we should be using more seep hose

 because you’re cooling your soils.

 Cooling that soil is really important

 and also keeping that soil cool

 and by using things like seep hose,

 that will then help to,

 you’re not wasting that water through trans-respiration

 when it hits the plant and dries off on the leaf,

 you’re actually getting it to the roots.

 So that’s what we need to do outside.

 If it was in a glass house,

 we dampen down to create humidity.

 In glass houses, we do it all the time.

 But in a glass house, that’s a controlled environment.

 Outside, what I deal with is very different.

 I’m sort of stuck with the weather.

 I can’t change my environmental controls.

 I’m stuck to what nature gives me.

 So generally, how we look at it now

 to manage the landscape at Kew,

 which is quite complex,

 is to have irrigation areas.

 We will use these irrigation methods,

 but we can’t irrigate every tree.

 So it’s down to all the research

 that are doing species selection

 to make sure that these trees

 have the plasticity or the adaption

 to deal with these long, dry, hot periods as well.

 So the seep hose, the seep irrigation,

 that’s actually something we use in our vegetable garden.

 And it’s one of the most efficient ways, isn’t it,

 that you can get water to your plants for sure.

 There’s no limited wastage, really.

 Yeah, and it’s the timing.

 What we’ve got to get away from

 is it depends on your soil type.

 So irrigation is actually very complex.

 So if you’re on a clay soil

 or you’ve got a lot of topsoil,

 an organic layer,

 you could irrigate through the night.

 So we would call that a preload irrigation.

 So you can irrigate through the night

 and you preload your system.

 So as the sun comes up,

 the plant then has the resources to go into growth.

 What we struggle with on sandy, free-draining soils

 is if you preload that soil through the evening,

 that water’s already gone through the system,

 through the soil system,

 before the plant goes into growth.

 So what we need to be better at

 is irrigating from first light till mid-morning

 and then evening into last light

 because that’s where we can then support those plants

 because they need that moisture.

 And that’s what we need to understand.

 And it’s very hard when you’re trying to explain

 to horticulturists or gardeners

 that you need to be very site-specific

 on your irrigation regimes,

 whereas we’re all used to,

 oh, we just turn the hose on at night.

 Because that’s easy.

 Yeah, and it’s more complex now.

 And grass, when our grass dies here at Kew,

 our temperatures, we can’t control it.

 So grass, when it’s green,

 cools down your surface temperature.

 I’ve recorded grass temperatures

 to 48 degrees this year.

 Because it’s all dried out.

 It’s all dried out and gone.

 Right.

 So then that retains heat,

 which then pushes nighttime temperatures up.

 So especially with urban heat islands,

 what we understand is now

 that that absorbs all that heat during the day,

 then radiates at night.

 So then you have a higher nighttime temperature,

 which means you don’t get a dew point.

 So you don’t get any dew on the grass.

 So then you are losing all your moisture.

 So those plants are then permanently stressed.

 They’re not getting a respite.

 Yes.

 There’s no respite, is there?

 That’s very interesting and it makes complete sense.

 So do you do anything with the grass at Kew?

 You’re not watering it because you just can’t, can you?

 No.

 But I’ve never considered how important it is

 to have green grass when it comes to your garden.

 Yes, this is the thing.

 I always thought it was aesthetic.

 So when ours has dried out, I’ve never really worried.

 I’ve just thought, well, that’s just summer for you.

 But it’s that cooling in our gardens.

 But that’s what’s really…

 So this isn’t my research subject,

 but Alex Summers, the curator here at Kew,

 would like to look at grass species

 and look at different grass mixes.

 Because this is a piece of research no one’s done.

 So we’ve just accepted the grass mixes

 that we currently use,

 and we’ve never thought any more about it.

 Also, grass management.

 Why do you think that is?

 Because we’re just obsessed with the Great British Lawn

 and we’re just going to irrigate it.

 Culturally, this is what I find really intriguing

 because culturally, the UK has never had to conserve water.

 No.

 If you think…

 So even I remember when I used to watch cricket,

 like the ashes or Wimbledon tennis,

 how many times did rain used to stop play?

 Yeah, exactly.

 They were permanently running on with rain covers

 to protect the pitch.

 You never see that now.

 Yeah, it’s so true.

 Because you think of Australia.

 So Australian gardens, for example,

 they have…

 I couldn’t obviously tell you what plant it is,

 but the grass looks kind of like grass,

 but isn’t actually grass.

 It remains green.

 It does a pretty good job of providing you

 with that green, inner verticom is lawn vibe.

 If you’re not too particular about the lawn

 that you’re trying to achieve.

 Is that the sort of thing that we should look at

 bringing over here and having in our gardens?

 Yeah, we need a lot more research in that.

 So you could then do various different mixes.

 So a lot of my work, I spend a lot of time out on the step.

 So the European step,

 so Southern Romania and Georgia,

 Azerbaijan, Kyrgyzstan, Kazakhstan,

 those environments.

 And that’s because we know that the Southeast

 by 2100 will be the same,

 what we would call a climate envelope.

 So the same growing conditions to what they have today.

 So we go there one to understand

 how the plants have adapted,

 but also to see what species.

 I think we need to do a lot more work

 around the grass species as well,

 but that’s not really, I’m woody.

 I don’t do green.

 So have we not been doing climate projection

 for longer than the last 10 years?

 Did we not see this coming

 and think, well, let’s try and preempt as much as possible?

 Or what happened there?

 Is it only more recent, I don’t know,

 access to tools and science and all the rest

 that has got us understanding,

 oh crap, we need to get our act together?

 Because it seems to have just kind of come on whammo.

 Oh my God, panic.

 Yeah.

 You can’t panic with trees

 because they’re pretty slow growing.

 Yeah, it’s really interesting.

 I think we all try to ignore it.

 Right.

 But also people like myself were,

 like I started this work really looking into this in 2012,

 2013, I started doing some projects

 with Dr. Andrew Hirons looking at

 how trees can deal with drought.

 But I suppose for me it was,

 we’ve got big data now and big data is available.

 So I specialize in selecting the right provenance of a tree.

 So where we source its seed from.

 So it has the ability to adapt to grow

 to our predicted future.

 How we used to do that in forestry,

 it’s been done for hundreds of years,

 but we used to collect the seed

 from every range of that plant.

 We would then grow it and watch it for a hundred years

 to then decide what one to use.

 That’s how forestry worked.

 So what I can do by using the wild observation of plants,

 so we pull down the data

 where a plant’s been observed in the wild.

 So it could be millions and millions of data points.

 That allows us to then look at those points

 and then we can match that in climate.

 So how it works is for every dot,

 so for every point where a plant is growing in the wild,

 I pull in its climate data.

 Now the climate data that I use

 and the files we use are one kilometer squares.

 So for most data runs,

 I will be using 10,000 observations.

 So then we pull in 10,000 one kilometer squares

 and all their climate data.

 We can then match that to a given site

 so we can understand

 what ones will suit our predicted future the best.

 So that allows us to do lots of screening.

 So we don’t have to grow a tree for a hundred years

 to understand which one grows the best.

 We can screen that right down really quickly

 to a couple of regions and that’s what we’re doing.

 And then we’ve been going plant collecting to those areas.

 So we’ve got those plants growing here at Kew

 from the trips that we’ve done

 and they’re all based around these modeling approaches

 which allows us to then screen trees

 to then select the better ones.

 And now we’re growing them here at Kew

 so we can then test them with scientific rigor

 and we can show and prove that these ones

 perform a lot better than our English natives

 or the ones that are available in trade

 and that’s what we’re working on.

 How much are you using AI in all of that process?

 AI could be really helpful.

 I’m experimenting with it

 but currently it’s all built through our script

 so it’s all built in computer code.

 So for me, I was a tree surgeon.

 I was a commercial tree surgeon for 10 years.

 Come to Kew and then I was a tree surgeon at Kew.

 Then I become supervisor.

 Then I become manager of Arboral Culture.

 Then I become head of tree collections

 and I’ve always studied, since I’ve been at Kew,

 I’ve always studied part-time alongside that.

 So I’ve come from being extremely practical,

 really enjoyed that but as my job progressed

 I then did the academia alongside.

 So I did a HND.

 I did a degree.

 I’ve done a master’s.

 Now I’m doing a PhD part-time.

 So I’ve taught myself research skills

 in order to understand some of the bigger problems

 and that’s been the interesting journey

 that I’ve done to do that.

 A lot of people just think I’m a career academic.

 I’m not.

 I’m dyslexic and I was a tree surgeon.

 Very practical background.

 It’s a nice balance to have though.

 So basically what we’re saying is you can do it all.

 What I find interesting,

 because I sit within an academic world now,

 is that I can look at things

 and that won’t work practically because I’ve done it.

 Which is needed.

 It is.

 You can have all the theory

 but you need to know the practice as well.

 And that’s why it’s been really interesting

 to select these trees because I can talk to trade

 because what we need now

 is a big shift with the commercial trade.

 They need to invest heavily

 in these new provenances or new species.

 So it’s not just about new novel species

 which I would always be interested in.

 That’s why I work in the Botanic Garden

 but what we need to remember also is

 we do have the British countryside

 and we’ve got biodiversity to manage.

 I’ve had discussions with the Woodland Trust.

 If we think of our English native,

 let’s use English oak as the easiest one.

 Everyone’s really passionate about English oak.

 We call it the English oak.

 The French call it the French oak.

 The Polish call it the Polish oak.

 It’s common oak of Europe.

 If we look to where Quercus rober, common oak grows,

 it grows from Ireland all the way out

 to the edge of Azerbaijan and northern Iran.

 So what we’re doing is we’re finding

 better suitable places to select the seed from

 where that tree has already grown under our predicted future

 and evolved to deal with that.

 They don’t look the same.

 They’re not the big English oak

 that we were seeing in the countryside in the UK

 but they will grow

 and they will form a better structure.

 So that’s what we’re looking at.

 So it’s understanding that as well.

 It must be so fascinating.

 So you talked about it on your video how,

 for example, we have a lime here in the UK.

 We need to consider the Romanian lime,

 the Azerbaijan lime,

 because it can cope with the drought

 but also still dealing with cold, wet winters

 because, of course, that’s what we’re also looking at.

 We’re not just going,

 well, everything’s drying out.

 Water is what we need because we then still are guessing

 and will, especially with super El Nino’s, for example,

 we’re likely to see some very wet spells too.

 We’re asking a lot from all our plants, aren’t we,

 to be able to cope with all that.

 So when you see a lime, for example, in Azerbaijan,

 it’s already dealing with that.

 We bring that over.

 Robert’s your father’s brother.

 Problem sorted.

 Kevin’s out of a job.

 Is that what we’re saying?

 Yeah, so what’s been really intriguing,

 especially you can get some gardeners that are quite lazy

 and just say plant Mediterranean.

 That’s not actually true

 because the Mediterranean doesn’t go cold.

 It doesn’t get a frost.

 We’re still going to have cold points

 within our seasonal calendar.

 They will be later, more March, April, May,

 but we will still go cold.

 Now, what’s really intriguing about the steppe environment

 or the sub-Mediterranean environment,

 they have the cold still.

 So the steppe, although it can go up to 40 degrees in the summer,

 it can go down to minus 20 in the winter.

 They’re dealing with wet as well.

 And they deal with the wet.

 So if you look at the steppe environment,

 their autumns are really wet.

 That’s predominantly when,

 autumn, early winter is predominantly when the rain comes in.

 So a lot of the plants are used to that

 and a lot of them are on glacial rivers.

 So they will flood in the winter

 and then by the summer, gone, dry.

 You don’t understand that until you go to places

 like Georgia and the greater Caucasus

 where you can actually see it.

 Until you go to these ecosystems,

 you learn so much by going to visit these ecosystems

 and understanding how everything interacts.

 And that’s what’s really important that we do that

 because we’re not just looking at data.

 We’re not just looking at what the computer says.

 We’re going out and seeing those environments

 and learning from that.

 And that’s what’s really important

 when we think about what plants

 we’re going to plant into the future in our landscapes

 is having that in-depth knowledge.

 We can’t just go on what we knew before

 because a lot of the people that I speak to,

 oh, that plant’s always growing well here.

 I was like, yeah, but you’re going on heuristic data

 or heuristic knowledge of that site.

 That’s what happened in the past.

 Climate is accelerating so quickly

 that we can’t rely on that information.

 We need to somehow be able to screen

 to understand the future.

 So to give you an idea, even at Kew,

 so Kew at the moment, if we just think of temperature,

 so temperature at Kew mean average currently today is 10.8 degrees.

 By the end of the century, it’s going to be 14.9.

 So that’s another, that’s four degrees shift.

 If we go back to my early childhood,

 so if you go back to the mid-80s,

 our average temperature is eight and a half degrees.

 Wow.

 Oh my gosh, that’s depressing, isn’t it?

 So that’s how far we’re shifting and how quick.

 So as I explained earlier, we’re in this acceleration now.

 We’re seeing this acceleration now.

 And that’s what’s really difficult.

 And what I find interesting,

 I’ve done lots of different pieces of work across the globe.

 Europe is the most affected by climate change.

 I think it’s because it’s where most of the industrialization happened early on

 and we have that concrete and we have that built infrastructure,

 which has actually increased the temperature so quickly

 compared to other less developed nations.

 I see.

 And that’s what we see.

 Okay, interesting.

 Oh, right.

 So when you’re looking, that’s interesting what you say about the industrial element

 and how that can have had an impact,

 because when you’re looking at what’s working well in Azerbaijan, as an example,

 with climate shifts, presumably, their climate is also shifting,

 but not so much because they’re not so industrialized around there

 and don’t have the impact of that.

 Is that the case?

 No, it’s still, it just seems to be Europe is most affected,

 but you will see that going out into Asia.

 They’re all shifted.

 They’re all going to get warmer.

 And that’s what I find quite worrying.

 If I’m going into areas like Azerbaijan to select trees,

 where do they go?

 This is my next question.

 Yeah, what happens there?

 And that’s the bigger research piece that needs to be understood.

 And what do you find to replace them as well?

 Yeah, it’s how much adaptation those plants can actually go.

 So how dry can those plants go before they die?

 Yeah.

 What’s their stress tolerance?

 So when you go to your colleagues over there,

 are they in a slight state of panic of, oh, God, where do we go?

 Not as much.

 It’s really, it’s hit and miss.

 I think it depends on the individual.

 No different to the UK.

 We will hear people that I talk to people

 that don’t believe the work that I’m doing is needed.

 Seriously?

 Yeah, you do.

 Oh, my word.

 It’s a generational thing.

 And it’s political suasion and everything,

 and true understanding of a subject.

 So you always get that.

 And we can all get stuck in echo chambers.

 Yeah, of course.

 It’s really intriguing that some places you go to,

 it’s just not on their agenda.

 But also Azerbaijan is quite a heavy oil nation.

 They do well out of oil.

 They’ve got other fish to fry, haven’t they?

 Exactly.

 So when you talk about the government

 and in terms of who’s on board and who’s not,

 and you give these talks and you educate as much as possible,

 in terms of the UK and our government,

 what are you dealing with?

 Have we got very receptive ears,

 or do we have a lot of pushback?

 Yeah, no, actually, a lot of the discussions

 you have in government are actually,

 they do understand.

 The last time I gave evidence in parliament,

 a report’s going to be produced of our recommendations.

 So there is.

 But I think we have to think about,

 the government’s got a lot to do.

 I think what we need to do as an industry

 is definitely talk about plants differently

 and talk about plants as engineers.

 That’s what I found gets more persuasion

 when you’re dealing with policy.

 So what I tend to talk about with plants

 is think about their function.

 So think about the function

 and why you’re planting it, like for trees.

 We can use ecosystem services,

 so cooling, shade, pollination, things like that.

 So what I tend to talk about with plants

 is the function in the urban environment,

 to cool the urban environment down.

 So it’s a way of cooling our cities,

 whereas our industry has always been thought about,

 oh, let’s just make it pretty.

 We’ll build a new business complex

 and we just put a bit of green

 just to make it look pretty.

 This is infrastructure.

 This should be called green infrastructure,

 and it’s to cool, it’s to mitigate,

 it’s to rain stormwater management,

 so rain interception,

 because if we go get more downpours,

 so we need that rain interception,

 so we need different canopy shapes,

 different canopy types,

 different leaf shapes,

 different leaf sizes

 in order just to dissipate rainfall.

 And then you’ve got the plants,

 but you need to select the right plants

 that can deal with this feast and famine.

 When we look at water,

 especially in the sustainable drainage system,

 everyone just plants wetland species.

 We don’t want that.

 We want these species

 that grow on the edge of the rivers in the steppe,

 because they’re used to this feast and famine.

 So they get a load of water,

 then it dries out again.

 They’re used to that in their system.

 So we need to use nature

 and learn from nature

 in order how we can then design our cityscapes.

 And I think culturally in the UK,

 we’ve had this thing about shade.

 I was a commercial tree surgeon.

 I spent most of my life pruning trees

 and cutting trees down

 because people didn’t want shade.

 I know.

 We are good.

 It’s such a good point.

 We had this conversation the other day.

 We literally did.

 We’ve planted so many trees.

 We’ve gone for buried trees.

 It’s one of the first things we did.

 We got probably planted at 100 trees in total.

 And in the early days,

 and we’re not going that far back,

 I’d say sort of six, seven years ago,

 I was all about,

 oh, we need to cut that tree back

 because I like to be able to sit in the sun.

 So let’s not have so much shade there.

 And then that changed partly laziness,

 partly also recognizing things were getting hotter

 and actually we needed shade more and more.

 This year we’ve let everything just go for it.

 And I don’t just mean trees.

 I mean, we’ve tried to grow as many climbers as possible

 to get a lot of vertical height to provide shade.

 For example, I can think of a jasmine

 that we’ve got that’s near the kitchen

 and it’s gone haywire at the moment.

 It’s up an arbor.

 And normally I’d keep it neatly trimmed.

 And this year I’ve let it go

 because it is providing so much shade towards the kitchen

 and against the walls.

 So our house is like a storage radiator,

 so the stones get hot and that’s it,

 you’re stuck with heat.

 So the appreciation of shade is massive now.

 It’s now our thing.

 Let’s get as much shade as possible.

 So it’s interesting you saying that,

 but I think people,

 generally the tide is changing, isn’t it?

 People are recognizing, oh God, we need the shade.

 Yeah, no, it’s really interesting.

 And this is where talking about,

 especially trees in a different context

 and not just they make things pretty,

 people may, especially when you talk to the general public

 and you’re trying to get people on board

 is that we need this shade

 and we need trans-respirational cooling.

 So when the trees are growing,

 that causes obviously they lose moisture

 from their leaves through that grain,

 which cools our air.

 And they’re the things that we need to talk about.

 So in government, they’re getting to understand that.

 We got to remember,

 they’ve already released a statement

 there was over 2000 extra deaths in May alone through heat.

 You know, heat related deaths in the UK now

 is getting to a large number

 and how cooling our cities down

 is going to be really important.

 So I got two young children,

 they’re both at primary school.

 So you think about routes into primary schools,

 we need to be planting shade trees

 because those kids are going to have to go to school

 and they’re going to need shade in their playgrounds.

 You know, if you think living in London,

 but you think about how many

 playgrounds in London actually have shade trees.

 And what frustrates me is they want to go to the park,

 but you can’t go to the park during the day

 because all the equipment is baked, is hot,

 because we’ve planted no trees.

 How many kids parks do you drive past or see

 and they don’t have any trees in?

 And they’ve got a metal slide.

 Exactly.

 And these are the things that we need to adapt

 and culturally, and it’s like leafful.

 How many times have I been in someone’s garden

 when I was a commercial tree surgeon

 and said, well, we want all these trees down

 because I don’t want to tidy up the leaves.

 I love trees, but just not in my garden.

 Right, because of the leaves.

 We know leaf mulch is one of the best things

 you can have in your garden, so.

 Yeah, it’s amazing stuff.

 But a lot of people don’t want, they don’t want it.

 So it’s that cultural shift which will take time.

 It’s a huge cultural shift.

 And again, you talked about that on Gardeners’ World

 and that was one of the things about

 you working with Elliot at Chelsea

 or getting the right trees to Chelsea

 and exposing the public to different varieties of trees

 and understanding what we need to be thinking about

 when it comes to trees.

 And you wanted to get that message across.

 Were you successful with that this year at Chelsea?

 Yeah, definitely.

 And it is becoming more and more near gender.

 And I do think a lot of the sites

 in the world of Chelsea is interesting

 because you need to get the garden designers on board

 because at the end of the day, they create the fashion.

 Chelsea is what drives the fashion.

 You can always tell what trees have been popular at Chelsea

 because they’re in every garden center.

 So for ages, it was like birch array with birch

 where it was really white stems and multi stems

 and everyone wants one.

 So that’s where getting the communication piece

 at Chelsea is so important

 because those garden designers…

 They’re the dodging cabanas, aren’t they?

 They are.

 So if we can get the garden designers on board,

 Arit Anderson, she did that great book,

 The Tree Selection Guide with my good friend Henrik Sjöman

 from Sweden.

 So Henrik, I’ve done research with for many years

 and I talk to Arit all the time.

 So it’s things getting people,

 influential people like that on board

 is so important because that’s what drives the change.

 Absolutely.

 So you feel that you’ve managed to get the word out

 to garden designers this year?

 Yeah, definitely.

 And I’ve had quite a lot of interaction

 with some that have followed up with stuff and questions.

 Good news.

 So the idea is that we look towards

 the thousands of exotics that are out there.

 We look at bringing those that are suitable

 more into the UK to try and mitigate

 these problems we have and the circumstances

 that our native trees aren’t dealing with very well.

 What then does the landscape look like?

 And I mean that both metaphorically and literally

 when we start bringing over these exotics,

 do we have any concerns with native trees

 and their place in the landscape?

 Or is that not concerned?

 Because the other thing is, of course,

 throughout history, we’ve brought over plants

 from elsewhere going, well, this will be great.

 And then, I don’t know, Japanese knotweed,

 for example, I’m all myself talking about that now,

 but that then became a big problem.

 We’re announcing that.

 Well, Alianthus, Alianthus.

 Yeah, a number of things.

 So it’s really difficult because with the research

 that we’re doing, you want those plants

 that have this really big range of adaptability.

 Now, that is an invasive trait.

 We have to accept that.

 We are looking for invasive traits.

 But it is, we have to still be careful.

 We can do data and we can look at where that plant sits.

 So for instance, it’s really hard without visualization,

 but Colateria paniclata, golden rain tree.

 Yeah, that is stunning.

 But by the end of the century, we look at where we are.

 So if we think of the UK

 and we think of our growing conditions currently,

 we are on its coldest, its colder, wetter edge.

 By the end of the century, we’re in the middle

 of its growing environment.

 So at 2100, we are perfect to grow it.

 Now, even I’ve seen it here at Kew,

 it is now producing seedlings it never used to.

 So those sort of trees, we can start to look at

 and go, yeah, you do have that.

 You do have the ability to become an invasive.

 The other one is Quercus ailex, the home oak.

 We have always been on its colder edge.

 By the end of the century,

 we’re right in the middle of its range.

 Okay, so what are we gonna do about that?

 It’s just using good horticultural knowledge

 and then when we look at the trade,

 it’s having that conversation

 and this continuous research that goes alongside this.

 So we can keep updating trade

 to what plants should be put forward

 to be grown commercially.

 And we’re still a long way.

 So that’s going forward.

 What about all those golden rain trees

 that have been planted throughout the UK?

 Yeah, that’s big policy.

 You’re laughing.

 Yeah, because it hopefully won’t be my problem,

 but it’s really interesting

 because what we’re gonna have to do,

 if we start seeing lots of seeds,

 we’re gonna have to start pulling them up

 and it’s gonna go down

 to good horticultural maintenance.

 Yeah, but again,

 then we’re back into the giant hogweeds

 along river banks.

 Exactly.

 Sure, well, we all pull them up,

 but not everyone’s gonna be pulling them up.

 So as long as we’re aware of this,

 we’ve got, what are we in now?

 2026, so 2100, we hit perfect.

 So we should be able to,

 hopefully you would like to think

 policy would be implemented

 to start managing those species

 as we go along.

 And that’s what we will probably see.

 No difference to allianthus.

 You can’t plant that now

 because it’s a thug.

 Right, interesting.

 A question I had was,

 when we look at plants,

 are you actually looking at trees

 over towards the Americas?

 So including North America

 and South America,

 because South America,

 they get the huge amount of rain.

 So it’s not quite,

 it’s like Chile, for instance,

 and Mexico,

 some plants in Mexico are no good.

 Yeah, of course.

 Yeah, no, there’s lots.

 So we’ve done big maps.

 So we did a global map.

 So we did a document

 that I’m gonna actually update next year,

 but in 2024,

 we released a document called

 Kew’s Landscape Succession Plan.

 And in that,

 we mapped our future climate

 across the globe.

 So we’ve got areas of interest

 and we can pick up areas in America,

 North America,

 where we can start looking for plants.

 We’ve always brought in plants from there.

 But what, so for instance,

 I find really interesting

 is the tulip tree,

 lyridengian tulipifera.

 If we get it

 from its wettest observation,

 it goes into stress very quickly,

 but it has a very big range.

 If you get the source material

 from the drier range,

 it’s absolutely fine.

 But then you’ve got its cousin.

 So you’ve got lyridengian chinensis,

 which comes from China,

 mainly in Sichuan province.

 That is the biggest wimp.

 That’s already dropped its leaves.

 And that’s what we’re gonna see now.

 So I don’t know,

 if you cast your minds back to 2022,

 there was a lot in the media

 about the false autumn.

 We’re already starting to see that now.

 So we’re already starting to see plants

 that are so stressed

 that they’re going into dormancy now.

 They’re dropping all their leaves.

 Because these plants are so stressed,

 they’re losing so much moisture

 from their system,

 it’s their final strategy.

 And they just go bang

 and drop all their leaves.

 And then try and sit it out

 till next year.

 So it’s like a live fast,

 die young strategy.

 How successful has that been

 for those trees that have done that?

 Have they managed to push through?

 Well, they’ve survived,

 but they’ve never truly come back as good.

 So you’ve got to remember,

 a tree is like a big back tree.

 It has lots of stored carbohydrates.

 So what’s interesting is

 how that would be fine.

 So everyone talks about 1976.

 That was seen as a once

 in a lifetime event.

 So that would have,

 trees would have dropped their leaves.

 And then for the next two decades

 afterwards,

 the weather pattern went back to normal.

 They could deal with that.

 But what we’re seeing with these

 environmental events

 becoming more common,

 those trees won’t have that period to restore.

 So it’s how many times

 can they use that strategy

 before they run out of energy?

 Because the back tree is running low

 and that’s what we’re starting to see.

 So you see like a lot of the

 Aeschylus species,

 a lot of the horse chestnuts

 from North America or the UK,

 they’re starting to do that now.

 I was looking at some plants from Japan.

 So the Katsura tree,

 that’s already going into leaf fall already.

 I’ve got some cherries

 starting to turn red already.

 Their leaves are turning red already.

 Well, they’re already looking at dropping.

 So what we will see

 in these really hot dry years,

 we won’t have that wow autumn.

 Kevin, let’s have a look at your dream garden.

 So to start off with,

 what would be the garden boundary?

 Garden boundary,

 I would have probably a mix of hedging plants.

 Okay.

 I would probably look at native species,

 but from their dry range.

 So collections from Romania, for instance,

 and out on the steppe.

 So you can get a lot of your hawthorns

 and your black thorns from there,

 and then your field maples.

 And then within that hedge,

 I would also have

 landscape trees as well.

 So you’ve then got like

 how the British countryside

 would have been pre-war

 when we dug for Britain

 and we took all those hedges out,

 we would have had big alms within that.

 So I would probably look at things like

 zelkova carpinifolia,

 which is a relation to the alm,

 grows from the steppe.

 I’d probably have that.

 So yeah, known as the Corsican alm.

 So I’d have probably plant that through there

 to get height and structure

 as well as having that green boundary.

 So a real variety in height.

 So Kevin, give us the down low,

 give us the inside scoop.

 Which country are we best

 to be having our dream garden in

 if we’re going to survive the next 100 years?

 Well, move in a garden there.

 Of climate change.

 Where would your dream garden be?

 Do you know what?

 Dream garden probably would be Gloucestershire.

 I reckon going towards Gloucestershire

 to the west there.

 Because we’ve got lots of soil.

 We’ve got lots of fertile soil.

 You’ve got over a meter of soil up there

 and it’s a bit of a clay mix.

 Also, you’re still going to get enough rain.

 The rain increases on the west coast.

 So our rain increases enough

 and it keeps in track with our temperature.

 It’s going to be three degrees cooler

 than London, for instance.

 So you would rather there than Cornwall,

 which is a lot wetter.

 And Cornwall has a tighter range.

 It doesn’t go quite so cold, quite so hot.

 No, I’d rather go in Gloucestershire

 then you’ve got topography,

 you’ve got the hills.

 I’m not really one for the coastline.

 I grew up in rural Hampshire.

 So Glasgow doesn’t interest you then?

 No, my brother lives in North West Scotland

 and I have enough going up to see him.

 Okay, so you want to live in Gloucestershire

 but have relatives up in North West Scotland to visit.

 Yeah, that’s it.

 But I still want to be able to grow step plants

 because that’s what my research is in.

 So if I go too north,

 I won’t be able to get the heat getting to grow.

 That’s no good, is it?

 Go now, fair enough.

 I’ve got to also keep in tact with my research interests.

 Yeah, that sounds reasonable.

 And is your garden going to be just rolling countryside

 or are you keeping things quite tight,

 like a neat little back garden?

 No, I’d like it to, yeah.

 So I’d like to experiment with

 how we can design gardens

 but have multi-layered ecosystems.

 So like woodland glade style plantings

 but in the designed fashion.

 And then with that long grass

 with wildflowers with paths cut through it.

 Lovely.

 So what sort of size, like an acre?

 Yeah, I reckon two acres for keeping them used.

 Yeah, a couple of acres.

 And in terms of having it designed like that,

 are there any designers that you feel are really on board,

 they’ve really got with the program who are advocating?

 Yeah, I like what Tom Massey does.

 Yes, well of course he worked with AI, didn’t he at Chelsea?

 Yeah, yeah, well I helped him on that.

 I was part of that.

 I was one of the consultant,

 well gave him advice on it,

 on the sensors and how to use the sensors.

 So I know Tom well.

 How successful do you feel those sensors are?

 Yeah, I think it’s a good communication piece.

 I don’t want to mind about the sensors

 from a scientific point of view

 because they’re probably not as accurate as what we would use

 but they do tell a very good story.

 It’s a start.

 It does and that’s what’s important,

 it’s the communication piece.

 But yeah, Tom, I like what Tom does.

 I like what Arid was trying to do this year

 so I spoke to Arid so I get on with her really well.

 I very much like how they design

 but I like that more naturalistic style

 but it still needs to be designed

 and it still needs to be bold.

 Yeah, okay.

 It can’t be too, I don’t like,

 I don’t like designed landscapes that are too safe.

 Okay, so you want to live on the edge a bit.

 Yeah, especially with species.

 You can imagine if you had a wood pasture style garden

 with long grass but then you had really,

 like you had trees like you,

 like I said, zelkova, carpina folia

 and you got like Quercus castana folia

 and Parotia persica

 and Tiliadila styla all mixed in.

 That would look really different.

 Yeah, okay.

 So I’m nodding there.

 You rattled off a whole load of Latin names.

 Yeah.

 None of which mean anything to me.

 Do you have any common names

 you could share with us to make it a bit easier on us?

 Like Cork and Elm, there we go.

 That’s the first one.

 So yeah, so you got like, yeah,

 so then you got Parotia persica,

 the Persian ironwood.

 Okay.

 Oh, I’ve heard about, isn’t that really,

 isn’t that, I thought that was really rare.

 Or am I thinking something different?

 No, it can be difficult to find in trade.

 We only have about 1% diversity

 of the actual species within the trade.

 I really, I want, I will get there

 to go to the forest in Azerbaijan

 where Parotia grows wild.

 Wow.

 And you can have from,

 so in the autumn they can go from yellow to purple

 in the diversity.

 Amazing.

 So that’s the type.

 Then Tididala styla.

 So interestingly, I identified that tree

 within my master’s research

 is one of the most drought resilient trees.

 And that’s the, again, the Corsican lime.

 We’ve actually got all of its provenances from Q.

 So it grows from Northern Iran into Georgia

 and then goes into Crimea.

 And then Quercus castanifolia

 is the chestnut leafed oak,

 which is my absolute favorite tree

 that’s here at Kew.

 And it’s our biggest tree.

 It’s over 30 meters tall now.

 And when I was climbing arborist,

 that was my favorite tree.

 And that tree, trying to understand

 why that tree grew so successfully at Kew

 is why I ended up in research.

 So that’s why I made the shift

 from being a tree surgeon

 into doing what I do now.

 I see.

 Because I want to understand

 why that tree grew so well.

 All because of that one tree?

 All because of that one tree.

 That does actually lead me to a question.

 Why did you get so into trees

 in the first place?

 What’s your background?

 My background?

 My dad was a tree surgeon.

 And I grew up here.

 That’ll do it.

 And to be fair,

 it was more to do with the chippers,

 the tractors, the winches,

 climbing and the chainsaws.

 And that’s what I wanted to do.

 So from about the age of eight or nine

 all I wanted to be was a tree surgeon.

 Wow.

 Because you saw your dad doing it.

 Yeah.

 And I just loved it.

 Outside, it was dangerous.

 You’re climbing trees.

 Everything a young lad likes.

 Like my son wants to be a rugby player,

 but then sometimes says,

 oh, I don’t know,

 I could be a tree surgeon,

 but I don’t be a tree surgeon.

 I’m not sure what’s safer these days.

 Both have their negatives.

 So you’re happy climbing a tree.

 Do you have a head for heights?

 You don’t?

 Yeah, I love it.

 So you have no fear of heights?

 No, I’ve always enjoyed it.

 I struggled not climbing

 because I missed the adrenaline rush

 and the buzz of climbing trees.

 Where do you get your thrills from now?

 Thrills are now coach rugby with the kids.

 But where do I get it from now?

 I still go and climb when we’re on expedition.

 Yeah.

 I suppose really it’s the buildup

 to when we are going on expeditions,

 probably the buildup to doing those expeditions

 because there’s a lot to get done,

 a lot of kit to get ready.

 It’s all the relationship building,

 finding the funding, getting the team together.

 That’s really where that buzz comes.

 So I just accept that every couple of years

 I get to have a good two weeks out collecting.

 It’s the buildup to that.

 That’s pretty cool.

 I can imagine everyone’s like,

 where’s Kevin?

 Yeah, there is that.

 He’s up a tree.

 Oh, there he is.

 Also, I’ve now learned to get lots of satisfaction

 and buzz from doing the research

 when you want problems.

 It sounds fascinating.

 A really balanced job to do.

 This is your dream job then?

 Yeah, I’ve sort of curated it to how I would like it.

 That’s the way to do it.

 You watch and learn, Sweetpea.

 That’s how you do it.

 I’m very fortunate.

 But it’s been hard work.

 All my studies and the same with the PhD,

 I do that all part-time.

 So I was on my laptop until half past 10 last night

 after work.

 So I have a very patient wife that understands.

 That is also the secret, is to have a wife.

 Yeah, I’ve got two kids.

 Well, they’re getting a bit, wow, yeah.

 They’re 10 and five.

 They’re getting a bit more independent now.

 I tell you what, if I would do it all again, Kevin,

 I would get myself a wife.

 Then I would be able to do all these amazing things.

 What would you like between a shed or a greenhouse

 if you had to choose?

 Shed or greenhouse.

 Shed.

 Oh, is this for all your tools?

 Yeah, tools, but also a lot of the trees,

 you don’t need the greenhouse to get them to strike.

 So a lot of them, you can just grow out in pots outside.

 And then, yeah, you’d have a standing out ground.

 But yeah, no, definitely a shed that I can hide in.

 As long as it’s a nice shed that I can have my office in there as well,

 that’d be quite nice.

 I see.

 So we’re looking at a fairly substantial shed.

 Yeah.

 Got some heating in there, a kettle.

 Yeah, a fridge, a beer fridge.

 Yeah, definitely a beer fridge.

 Obviously a beer fridge.

 And then I’d have a section just for all my fishing stuff.

 Okay, so an outbuilding is what we’re off.

 No, it’s definitely going to be a shed.

 It’d be a timber shed.

 Okay, a big shed.

 A big timber shed.

 A log cabin.

 Very nicely made up.

 Log cabin, yeah.

 Okay, great stuff.

 And so a fire, heating in there, a fire perhaps?

 Yeah, a log burner.

 All right.

 And then in terms of when you’re growing your trees from seed,

 so you said then that they can mostly be done in pots.

 You don’t necessarily need a controlled environment like a greenhouse.

 All right.

 So literally, so I mean, there’ve got to be some trees though

 that can only be grown in a greenhouse?

 It is easier to get them to grow in a greenhouse,

 but if you’ve got enough shelter and shade,

 you’ve got to think, look at how they grow.

 You’ve got to remember the environments that I go to, like the step.

 That’s how nature grows them.

 They drop seed and they grow in the soil.

 So all you’ve got to try and do is mimic nature.

 So sometimes here at Kew, when we bring seed back, we mimic winter.

 So we would put them in cold stratification.

 So we put them in a fridge.

 So you’re just mimicking nature.

 So if you’ve got them outside, depending on when you collect them,

 they’re going to get that cold period.

 Plus you’ve got your bare fridge.

 Exactly, so yeah, certainly that.

 So trees are easier to strike off on benches outside.

 Well, what would then be your five favourite ornamentals?

 Per chance.

 Five ornamentals?

 See, my wife does the green and squishy stuff in the garden.

 The green and squishy stuff?

 No, I quite like roses.

 Bosh.

 Yeah, I’ve always had a keen interest in roses.

 So I’m probably blonde.

 Isn’t that just some of my friends take the mick out of me for it?

 Why do they take the mick out of you for it?

 Because they just said it’s so, yeah, basically,

 and it’s a bit weird that you’re into trees,

 but then you like roses.

 But anyway, yeah, no, probably roses, to be fair.

 Any particular type that you can think of that particularly catches your eye?

 No, I just like having the scent and the flower and the structure of them.

 I think I would like to try and plant them under trees

 to see how they would perform and try to do something a bit novel.

 And the other thing, hydrangeas.

 I like hydrangeas, but unfortunately,

 we don’t have enough moisture really to support them.

 Might be right in Gloucestershire though,

 if you see everyone wet higher up.

 Not an ideal plant with climate change, are they?

 No, hydrangea quercifolia I’ve always liked.

 Yes, stunning plant.

 So with the roses, of course, you can get your ramblers and climbers.

 So Monty, for example, in his garden has one growing up through his trees.

 Does that appeal to you, having that kind of set up?

 It would, yeah, as long as I haven’t got a climbing prune.

 Then you can release your desire to get up there.

 Yeah, exactly.

 I would like to do that because I think it could look really intriguing.

 But you would want to manage it so it doesn’t overtake the tree.

 So you’d want to manage it.

 It would be good to do if you had an avenue of trees

 and then you had rambling or climbing roses up them

 and then managed them, could look quite interesting.

 Is there a particular colour of rose that appeals or you like all of them?

 No, I like all of them.

 I like the more pale colours.

 I don’t like the big garish ones.

 But I like the pale ones, like tea roses and stuff.

 Are there any ornamental trees that A, you like,

 but B, you would also recommend?

 Because I know one of the things we have to culturally,

 that cultural shift we need to have is to get away from

 growing trees just for the aesthetic.

 So the Japanese maple, for example.

 But there are then still plenty where, obviously,

 we want the flowers for the pollinators.

 The berries for the birds.

 Exactly.

 There’s so much diversity out there.

 I just think what we have in trade is so small

 and what we accept as an ornamental.

 I think what will happen over time is

 our perception of an ornamental will change.

 So instead of things like the Japanese maples,

 we could look at things like ace of Tarcarica,

 for instance, which comes from the Caucasus.

 Let me have a look at that one.

 It’s got like a pink, its seeds are pink

 and it goes a real nice colour in the autumn.

 Oh, yes, lovely.

 So I think trees like that, I think,

 will be the new ornamentals and they don’t get too big.

 And I quite like, you don’t see it in the trade very often,

 which is the Oriental hornbeam, Carpinus orientalis.

 That’s got a really nice, small, delicate leaf.

 Oh, okay.

 Just checking that one out.

 Oh, that’s pretty.

 That’s a cool choice.

 That’s got a little delicate looking.

 It’s very delicate looking,

 but I’ve seen it growing in the wild

 and it’s a tough old plant.

 So that would be something that would work well here.

 Yeah. So those trees like that,

 I think, will be our new ornamentals.

 Yeah. And you’ve got one more,

 if you had to choose one more ornamental.

 I’ve always liked, and I’ve planted one at home,

 is Magnolia grandiflora.

 Yeah, they’re amazing, but they’re difficult.

 Oh no, what’s the but?

 They’re really big wimps when it comes to drought.

 So it’d be the one that you’d have to invest a bit of,

 you’d have to accept you’re going to invest

 to keep that one irrigated.

 Yeah. Oh, what a shame.

 That’s sad to hear.

 They are the most gorgeous trees.

 I think the one at home is doing so well

 because I think it’s got its roots into the drain system.

 Oh great. That’s going to help.

 Yeah, just bury your head in the sand about that.

 You’ll move house before that becomes a problem, right?

 Yeah, I hope so.

 Yeah, exactly.

 What would then be your five favourite edible plants?

 Edibles?

 Oh, right. I’d have hazel for the nuts.

 Walnut.

 Yeah, that’s a good choice.

 And then I would probably have…

 Not the black ones.

 Not the black ones.

 And then, oh, what else?

 I would have black form for slow berries to make slow gin.

 Yeah.

 And then last one, what could we have?

 We’ve got two more.

 Two more?

 Probably good old blackberries.

 Yep.

 For the kids.

 They like picking them.

 Are we counting blackberries as a tree?

 It’s not really a tree, is it?

 But you can grow it.

 Oh, sorry. We’re not doing trees.

 No, this is…

 Ignore me there, Kevin.

 I’m setting all the batteries up.

 Just because Kevin loves trees.

 Don’t force him.

 I’m so in tree mode right now.

 Yeah, no, no.

 That’s not a tree.

 You can’t climb up that thing.

 I’ll allow blackberries, yeah.

 Totally ignore me.

 Yeah.

 Blackberries.

 Any other berries like that, then?

 Gooseberries or raspberries?

 Yeah, gooseberries or raspberries

 because we all like those summer fruits.

 So not rhubarb?

 There’s no veg that you eat?

 No, because I won’t have the patience

 all the time to do it.

 But also, I think as the climate moves,

 those berries are going to become a lot sweeter

 and a lot of people will eat them.

 And you get more crop.

 So every cloud has a silver lining.

 But then if we’re really going that direction,

 are there any sort of more exotic fruit and veg?

 I’m trying to refrain from saying trees

 because I feel I’m forcing you down a tree.

 But for example, I don’t know,

 pawpaws or avocados or mangoes, bananas.

 I think we need more humidity for them

 because the bigger the fruit, the more investment.

 So it needs more resources to build it.

 Avocados grow well in California, for example.

 Is that a good humid climate?

 Yeah, it’s fairly humid there in some parts of it

 because it won’t grow across all of California.

 But even the fact that we had some avocado plants

 just from the compost heap

 from just some stones that were chucked on.

 And I planted those in some of the veg beds,

 which has that kind of drip seeping irrigation system.

 And I left them out

 and then they went completely brown over the winter,

 obviously because we get harsh frosts.

 And I thought, oh, well, that’s them done.

 And I was going to cut them back.

 And then all these shoots have started coming up from them.

 And I could not understand how on earth that was happening.

 They looked so dead beyond belief.

 Yes, they did.

 I thought they were gone.

 It’s the storage system in the root system.

 It’s the stored carbohydrate.

 Well, that’s really good news.

 I’m glad they come out.

 I hadn’t noticed.

 And what about lemons?

 Sort of citrus.

 They’re good.

 Yeah.

 No, we can, lots of citrus fruits

 will be able to grow in the southeast.

 A lot of white, they’re doing a lot.

 Yeah.

 And then obviously you’ve got grapes for wine.

 Yep, grapes.

 They’re going to flourish, aren’t they?

 Yeah, yeah, yeah.

 We’re going to be able to, especially in the southeast.

 You might have a wine in a very…

 Well, we’ve got a bigger wine industry now.

 But it might get bigger.

 It’s continually improving, isn’t it?

 So it’s not all bad news?

 No.

 Good.

 Completely dark.

 Well, then what would be your one statement tree?

 I’m sorry for you.

 We’ve had to give you just one.

 One statement tree?

 Yeah.

 My statement tree or a statement tree?

 It would probably be the chestnut-leaved oak,

 to be fair, my statement tree.

 Even though you’ve already got that?

 Yeah, but I didn’t plant it.

 I would probably have a mix of it from wild source,

 but then in the middle of the garden,

 I’d definitely have that growing right in the middle.

 Statuesque one.

 Statuesque one.

 Because it means so much to me personally because of research,

 but also it’s leaf as well.

 What about its leaf?

 Well, it looks like a sweet chestnut leaf.

 Okay.

 But it’s an oak.

 And you recommend that’s a tree we look at growing in our gardens?

 Oh, 100%.

 Okay, that’s going to survive.

 You can find it in the trade.

 Where do you recommend for getting these sorts of things?

 Hylia’s tree nurseries seem to be the best one down in Petersfield.

 Okay, yeah.

 I do a lot of work with them.

 They’re now starting to try and get more of these novel species.

 Well then, would you like a pond or a pool?

 And what plant would you have in that area?

 Pond.

 Definitely have a pond.

 Big, small.

 Massive pond.

 Lake.

 Massive.

 You can have a lake.

 Have a lake.

 Then I can put fish in it.

 Oh, you like fishing and fish.

 Yeah.

 And then you can go fishing.

 Then I’ll go fishing in my own garden.

 And what would I plant around it?

 I plant lots of willows.

 I like willows.

 If you’ve got a water source and it’s sustained

 and it’s a stable water source,

 like you probably get from Gloucestershire

 because you’ve got the groundwater reserves refilled in the lake,

 I would definitely look at things like willows and taxodians.

 Okay.

 The swamp site for us?

 Yeah.

 We’ve been visiting quite a few gardens off late

 and we see that as a pretty popular one in the big gardens.

 Yeah.

 And it’s such a striking tree, isn’t it?

 Yeah.

 And if the roots go into the water, you get the eumatophores,

 which are like snorkels.

 Knees.

 Oh, so you describe them as snorkels.

 So what do you mean by that?

 So are they using that so they don’t drown?

 Yeah.

 So it gets gas exchanged,

 because obviously it can’t breathe underwater,

 so it puts a eumatophore up,

 which then allows the gas exchange into the root system.

 Well, final question is,

 what would be your favourite seating area,

 drink and plant to have in that area?

 Wow.

 See, I would have a-

 Fallen tree.

 Yeah.

 I’d have the seat up in the woodland glade.

 Yeah.

 What kind of seat?

 In a tree?

 In a tree house?

 No, I wouldn’t have a tree.

 It’d just be a nice bench.

 Okay.

 With a pint of Guinness.

 Definitely a pint of Guinness.

 A pint of Guinness.

 And your seat is just a bog standard bench, is it?

 Just a bog standard bench.

 Nice one.

 A nice comfy wooden bench.

 Okay.

 And then what would I want plants would be around it?

 Actually, I’d just have it around the tree,

 just be happy enough just to sit under the trees

 and admire them in the different lights that come through,

 especially in the evening.

 Any other tree that you’d like to choose, add in there?

 What tree could we put in there?

 Actually, to be honest, you could probably put,

 I’d probably have an English oak,

 but from the dryer range,

 so from probably Georgia or Romania,

 Quercus rova.

 Romanian oak.

 Yeah, yeah.

 Put Quercus rova, common oak,

 just so you can see it.

 And then, yeah, just so you can watch it.

 Actually, no, I reckon silver lime by a bench,

 actually, because it smells really nice in the evening.

 Oh, okay.

 So let’s go for a silver lime.

 Tilia tormentosa.

 Silver lime.

 And where’s that typically found?

 I’ve collected it from Romania and from Georgia.

 It mainly comes in Southern Europe, Southeast Europe.

 Okay.

 Okay, very cool.

 Well, I’m going to read back to you quickly,

 your dream garden, just in case you’ve messed anything up

 or you want to change anything.

 So first of all, we’re going in the Gloucestershire area.

 We’re wanting about two acres.

 It’s going to be designed very boldly,

 lots of long grass and paths cut through it,

 woodland glade, we’re going for that.

 Then you’re having a mixed hedge, dry range,

 so natives, hawthorns, blackthorns,

 with also landscape trees in there,

 like of course, you can have the chestnut leafed oak.

 Then you wanted a shed,

 but it’s going to be a little bit for tools,

 but mainly a place to hide in, have your office,

 have a beer, a fridge, but also for seeds,

 fishing stuff, and a log burner.

 Then your five ornamentals, we have roses,

 some going up the trees, hydrangea quercifolia,

 acer tataricum, oriental hornbeam, magnolia grandiflora.

 Your five edibles, hazel, walnut,

 blackthorn for the sloe gin,

 blackberries and gooseberries or raspberries, you decide.

 Then your one tree was the chestnut leafed oak,

 that was the statement tree, whack it in the middle.

 You wanted a lake with fish in it so you can fish,

 and willows and taxodiums around that.

 And then you’re going to have a nice bench,

 a pint of Guinness and a silver lime above you.

 That’s it, that sounds about right.

 It sounds pretty good.

 Now, I had one question that we had with a previous guest.

 He had his statement tree as being something that he described,

 this is actually Diarmuid Gavin,

 who described it as the Chatham Island birch,

 and then we all three spent some time Googling the Chatham Island birch,

 but we couldn’t find it at all.

 Basically, it grows tall, thin and is really ugly.

 Does that narrow it down for you at all,

 that you’d be able to now put this one to rest

 and tell us what tree he was talking about?

 No, no, it could be any birch.

 They all grow like that, to me as well.

 Okay, so a birch that grows on Chatham Island.

 Chatham Island, it’s probably the native birch, I would have thought.

 I couldn’t find that either, to be honest.

 Yeah, no, I don’t know that one.

 All right, not to worry.

 Well, that’s your dream garden, Kevin.

 Thank you very much.

 We’ll see if we can get that sorted for you.

 That’d be nice.

 And it’d be very interesting to see how we go with this

 working on the green infrastructure, isn’t it?

 Yeah, including the urban areas, including the grass.

 And hopefully we can make strides with that in the UK.

 Well, thank you so much for your time.

 That’s been a good old chit chat with Kevin.

 Thank you, it’s good fun.