Episode 217: the Barbican Conservatory

The Conservatory at the Barbican is filled with lush growth. Photograph: Max Colson.

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Transcript

Episode 217

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Jane: If you're investing in grow lights it pays to choose something that's high quality and stylish and that's where Soltech Solutions comes in. Their range of full spectrum photosynthetic plant lights are both sleek and modern and they'll look right at home whatever your decor. I know that because, well, I've got some. I took delivery of one of their bulbs and it screwed straight into my standard floor light fixture for a super quick setup, but if you need pendant lights or track lights, Soltech Solutions can help too. When you buy a Soltech Solutions light it comes with a five-year warranty, so you can rest assured that your light is going to last. Check out Soltech Solutions range of lights now at Soltech Solutions.com and get 15% off with code OnTheLedge, that's SoltechSolutions.com and enter code OnTheLedge for 15% off.

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Jane: To plant, or not to plant, that is the question. That's a terrible question! The answer is obviously to plant but there is a small theatrical angle on this week's show as I head to London to discover a hidden horticultural gem.

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Jane: My name's Jane Perrone, host of this podcast On The Ledge, the aural destination for all things houseplant related. In this episode I visit the Barbican Conservatory in the great capital city of London to find out about the incredible plant collection there and I answer a question about a Kentia Palm.

I do hope you've had a fabulous week. I've been doing my annual spring clean of the shed, it took so long and it's still not finished but it's very satisfying to clear up the disaster area that was a lot of spilled potting mix and all kinds of mess. The shed is also home to my hardier, not hardy, but hardier cacti and succulents, so they've had their first watering. I need to go and check on them and make sure the whole thing hasn't collapsed into a pile of mush, so fingers crossed.

The Plant Ledger is out, if you've subscribed, you should have received a copy in your inbox, if you haven't subscribed, remember it's only going out to people who have actually signed up specifically to The Plant Ledger, you can sign up at JanePerrone.com there's a big link that says The Plant Ledger. I'll also put a link in the show notes to this episode. It's my roundup of the UK houseplant scene, you don't have to be from the UK to subscribe but lots of the stuff in there is relevant to you if you are.

On the Patreon front, Irina became a Ledge-end and Lauren became a Crazy Plant Person. This coming Sunday, 10th April, 2022. I'm hosting two Zoom sessions for Patreons at the Ledge-end and Superfan level, one for each of those tiers. You will have a message in your inbox from me with that Zoom link if you are a Patreon subscriber at those levels. It's a chance to just chat, no set agenda, just a chance to have a chat with me, so please do come and join me. If you're not a Patreon subscriber and you want the chance to join these kind of things then check out the show notes for details on how to do that. Thanks also to LozzaP in the UK for leaving a lovely review for the show.

I've heard from several people saying thank goodness you got rid of that water noise and, if that's you, I'm really glad that you're happy about it but it emphasises my point, said before and I'll repeat it again, if there's something you don't like in the show, if I've made a mistake, even if it's just a typo in the show notes, please do let me know. Don't assume that somebody else is telling me this stuff because it's hearing back from you that enables me to make the show better, so any errors, mistakes, constructive criticisms I would love to hear them and you can drop that to OnTheLedgepodcast@gmail.com I read everything and try to get back to as many people as I can.

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Jane: I can't believe I've been travelling to London for visits all my life and yet I'd never been to the conservatory at the Barbican. The Barbican is a really famous part of London, you may recognise it from its brutalist architecture, basically it's a massive lump of concrete and its very fine theatre. The last play I saw there was Mr Benedict Cumberbatch in Hamlet, yes I was in the front row, yes I enjoyed every minute of it. But, you may not know that The Barbican is also home to the second largest glass house in London. I met head gardener Marta Lowcewicz to find out more.

Jane: Well, thank you very much on this snowy day, well, it's not actually snowy in London but I can tell you there were heavy flurries on my way from Bedfordshire, so it felt rather strange as I was coming into this rather less snowy environment of The Barbican Conservatory. We're stood here and there's a lovely… is that a robin singing in the background?

Marta: It is. Actually, we've got two robins and they are starting to build their nest in here.

Jane: Oh, that's so nice. Well I'm glad there's some wildlife enjoying the trees because you have got some really big trees in here. A high ceiling set around this central concrete tower, the classic Barbican architecture. Lots of people don't know about this place, tell us a bit about how it came to be here.

Marta: As you probably know, or may not know, we're based in the city of London in the heart of London, basically. This part of the city of London was heavily bombed during the Second World War simply because of the proximity to St Paul's Cathedral and after the war, obviously, lots of buildings were in ruin. So the City of London Corporation came up with the idea that they're going to build a new space that gives people somewhere to live and enjoy themselves. That's how they came up with the idea of building the Barbican estate and, obviously, the Barbican centre. So the project was designed by three architects, Chamberlin, Powell and Bon. In the process of designing it, and we're talking about 50s and 60s so that modernist, brutalist architecture, during the process of designing they have to design the theatre and in the old-fashioned theatre, I was told by the architect, they have to build what is called the Fly Tower. So the tower that holds all the flyers, the backgrounds for the theatre. As you can see it's in front of you, this massive concrete monstrosity, it was a little bit ugly looking, so they tried to disguise it by building a conservatory around it. On the original architect drawings you can see that there was always an idea to build a glasshouse in here. The original ones were actually designed as a pyramid in the Louvre. So that was that triangle shape but, obviously, with the time it evolved into this place. So the Fly Tower actually divides the conservatory into two spaces, the west-facing space and the east-facing space, simply how we are orientated around the world.

Jane: This shows the power of plants really to take, as you say, this brutalist architecture and soften it with lovely plants. So we've got some hanging plants, I can see Monstera deliciosa up there, I can see Dracaena trees, there's lots of lovely plants in here. What climate is this kept to?

Marta: We are London's second largest glass house after the Temperate glasshouse in Kew Gardens. We have a separate similar temperate regime, so we are a temperate glass house. The temperatures in here will be as low as 11 degrees (Celcius) in the winter and, obviously, as high as possible in the summer. We have a section for our Aroid or succulent plants, where the temperature will fall as low as 8 degrees (Celcius) in the winter. It's all heated but, as I said, the heating is kept to minimal for the plants to survive and live.

Jane: You're in a heat island, the City of London, and this is your own little heat island but it's not that hot, as you say, it doesn't feel a sauna-like environment, it just feels comfortable, doesn't it?

Marta: So when people think about it and see it on the photos they think it's a tropical jungle. We mimic that but it's not a tropical jungle feel. So if you were lucky to travel to a tropical jungle you can imagine that heat and mist. Sometimes in the summer, if we get more hot summers in London, especially due to the climate change, it will get hot in here but people say: “Why don't you spray more water?” If I spray more water in here it would be like a sauna as you said, too hot, you couldn't breathe. It happens sometimes, if we water on a really hot summer day, we try to water in the morning, so when the water evaporates, obviously, the heat… it’s not the heat, it's the humidity of it that we’re not used to.

Jane: Yes, that can get pretty unpleasant. I can imagine there are some challenges to gardening in this kind of environment, not least handling some of these very, very tall trees and climbers coming off these balconies. Do you have to get out the climbing rope sometimes? How do you keep it looking good?

Marta: Yes, so basically when The Barbican was designed as a building back in the 50s and 60s, health and safety was not in their agenda. So although it looks lovely we sometimes have to put a lot of climbing gear, safety gear on to go into and do some plants. We came up with some weird and wonderful ideas, we use lots of long pole saws to cut some plants that we can’t access. If there's something which we can't do, we try to call in every year the arborist, so they will reduce the crown of our trees because they will grow and eventually we cannot move the roof, so we will try to reduce the crown for the trees to fit within the conservatory. By doing that we allow more light for the lower growing plants to thrive in the spring and summer and the winter months, especially.

Jane: I can see a real diversity of plants in here, tell me about some of the stars of the show.

Marta: So we’ve got 1,500 species in here, 300 of them are succulents and the cacti. The stars, it's tricky to say because we’ve got so many individual plants that’s really, really difficult to pinpoint. We’ve got some rare endangered species. We’ve got an Obetia ficifolia, it's a nettle family tree and it's actually endangered in their native habitat. By the way we didn't go there and poach them; they were donated to us and happened to be there. Especially in the cacti section, we’ve got lots of cacti from Mexico like Lophophora williamsii, Peyote, that is endangered in the wild native habitats. Wherever you look, probably each plant during the whole growing year here is a star for different reasons because we’ve got a collection of Pelargoniums, they will be stars during the summer months. In the late summer, early autumn, they probably would be overtaken by chillis with all the weird and wonderful shapes and things like that. In the winter, we’ve got orchids, cold glass house orchids. We've got some Cymbidiums now that are flowering, so it's ever-changing. We've got Birds of Paradise and what is wonderful in this place, when people come in here and because London is so diverse, each plant brings back the memories for them of their home, of their parents, of their travel. So for the people who visit us, different plants are different stars basically, so that's how I try to measure the success of the place or the stardom of the plants, if that makes sense?

Jane: That does make sense and you're right, somebody can have a plant that sparks off a particular memory of home or relatives. I guess the one that possibly is iconic is the Monstera deliciosa and you really are showing how this plant, even though it's growing up concrete, you're showing how this plant grows as opposed to how we have it in a little tiny pot in the house because it's romping away up this wall here. Is that one that people particularly want to photograph and look at?

Marta: If you go through Instagram feeds, that's probably one of your popular platforms now to go through, you will see that one of the most photographed plants in here will be Monstera deliciosas and we do have the variegated versions in here that are quite old and they show the lovely variegation of them, but you're right, that's how they grow in their natural habitats in Mexico. They sort of semi-climbing, trailing just create a massive abundance of leaves. When we think about them in our average houseplants, we buy them as a little, little cutting. Sometimes they don't even have the fenestration, we wait for the fenestration, but people don't realise generally how big they will grow. I've got it with my own sister, she's like: “Oh, I'd love to have them,” I said: “Do you realise your flat is not big enough to sustain that plant?” If you look on the majority of those plants, you probably can recognise them from your houseplants because they are your houseplants just grown to the size of the space, basically, that's what happened with them here, we let them loose a little bit.

Jane: Is that an Araucaria, Norfolk Island Pine there that I’m seeing?

Marta: Yes, that’s an Araucaria heterophylla.

Jane: Again, another plant that people grow as a houseplant but here you're seeing its potential to get very large and very beautiful, but yes I think lots of people struggle with that but it's a really beautiful tree. What are these trees on the other side here, you’ve got four really tall trees here which I can't immediately recognise but I'm thinking Ficus?

Marta: Yes, you’re thinking right. If you think about 70s and 80s, that is your staple for every household, so it's Ficus benjamina.

Jane: Oh it is! Okay, you look at that and go: “Oh yes, that's why that plant hits your ceiling and gets too big,” because they’re enormous.

Marta: Exactly, they are absolutely enormous and as I said before, every year they get pruned and the crown gets reduced by two-thirds actually.

Jane: Yeah, wow.

Marta: So you can imagine how quickly and how big they can grow in the right conditions.

Jane: Yes, that's amazing and you don't have the problem that people have in their homes of moving them about and then all the leaves falling off because these are presumably planted into the ground, how is the soil set up here?

Marta: So the funny fact is that we're based on the third floor, so underneath are offices, theatre and all the things that make Barbican working. Our beds are not super deep, on the deepest points they are 1.3 metres deep, some of them are shallower and the Ficuses were planted as little babies. If I showed you the archive photos they were just the size of your average houseplant and, over the 40 years they've been here, they’ve just grown to the size that you see, so those two/three floors almost.

Jane: It's really interesting to see what their bark actually looks like because we're not really used to seeing that, they've got lovely smooth, very pale grey bark, which is actually rather lovely.

Marta: Yes, if I look on them in the right mornings or when you catch the light, it's almost like it’s glistening, some whiteness to it.

Jane: Yes, it’s beautiful. There you go, that's another example of how we underestimate the potential of houseplants to get huge. Is there anything here that perhaps wouldn't be well known as a houseplant but could work in a home setting, things that you might be able to try at home that people don’t grow?

Marta: So there is one particular plant that is my favourite and I always recommend it for the dark corners in the houses that people mostly struggle with. It’s a well-known plant but it's a little bit forgotten at the moment, it’s an Aspidistra…

Jane: Elatior?

Marta: Elatior!

Jane: One of my favourites as well. Although, yes, it's funny isn't it, because I think it's coming back now? People are starting to grow it again.

Marta: It is, yes. There is a smaller version which is Aspidistra crispa and it has white dots on them and there's even rarer version which has a variegation on it, so you can have the leaf variegated with with white because variegation is not necessarily white, it can be yellow as well just to clarify.

Jane: Yes, well that is a good choice and one of my favourites. Although, I have a variegated one but I found that the variegation indoors just didn't come very well and I put it outside and the variegation seemed to flourish, so I don't know whether that's just probably light.

Marta: It is, all the variegations are related to the light. So the more light they get the variegated plants they will come up with better variegation but, equally, I'll go back to the variegated Monstera, you see it on the photos of beautiful leaves with hardly any variegation, they're almost white, if not white. If they were planted on their own they would not survive because they don't have enough chlorophyll in them to sustain them and keep them growing. So, yes, the variegation is nice but you don't want to encourage too much of it and you'll probably notice as well the variegated plant will grow slower because they will need more chlorified green to keep them going.

Jane: Yes, it's a trade off, isn't it? This place is open to members of the public part of the time, so if people are coming to London they can look on The Barbican website, do you have a book in advance still? How is it working now?

Marta: At the moment you have to check for the dates because we share the space between lots of different types of events but all the dates are released roughly two weeks in advance. So it's best to check on the website, pre-book the ticket and all the dates and tickets will be released in half-an-hour slots still, I think, but the tickets are free of charge, so you can get in here and we won't charge you anything and you can spend as much time as you want inside of here. As I said you have to just pre-book it in advance, it's super popular unfortunately if you want to get a ticket.

Jane: I bet.

Marta: I will give you a good tip, sometimes on the day there are some extra tickets released, so if you're not lucky you can try to do it on the day.

Jane: That’s a good tip. Do you have any problems with people who don't realise that it's not okay to take cuttings of plants from your space?

Marta: I think, yes, I think like most of the spaces like Kew, Chelsea garden and any space that you can imagine that have got a collection of plants, and especially houseplants, that have been so popular and even during the pandemic. If you have a collection of rare plants, yes, people think it's okay to take a cutting or they will ask us and we say we're really sorry but we don't donate or give away cuttings or even sell them. Because simply if I had 100 people within a week to ask for a cutting there will be no plants left, basically. Some of them are very, very, very difficult to obtain, to propagate, to grow but, yes, there are some people… we have some information to try to discourage people from stealing them or taking cuttings but, unfortunately, it happens.

Jane: Yes, and you're right, it's a problem across all gardens that are open to the public. I'm noticing a couple of other plants that I just wanted to mention. I'm loving that, I can never remember what the current Latin name is, the purple Tradescantia up there, coming down, trailing down off the balcony there.

Marta: The old Latin name Tradescantia ‘Purpurea’.

Jane: Has it changed again, I can’t remember now?

Marta: With the botany and the names, it changes constantly and you have to be really quick to keep up with it.

Jane: I think it's commonly called Purple Heart or something like that but that looks so stunning the way you’ve got it pouring down off that balcony. Is trimming that a challenge?

Marta: Yes, it is a challenge on its own, you can see some of the window boxes have been trimmed, so we try to do it at the same time as the arborist comes, so we get a good clear out in the conservatory and then everything is ready to grow. We don't trim them every year, we try to keep them trimmed every few years but, yes, it is a challenge, it's surprisingly a lot of plants. It doesn't look from the bottom like that but it’s a lot of plants.

Jane: Yes, I'm sure and I'm sure when you lift up that and look at the back of it, I always find with big trailing plants like that, the back is another challenge all together and remove dead leaves.

Marta: It is and sometimes if I go there I think: “How on earth are they growing?” because there’s not a lot of soil that they have in that window box and how on earth are they holding together because you touch them and sometimes they're quite brittle. I think for that abundance of that they just create that fantastic thing.

Jane: It's not a green wall, it's a purple wall, but it's very lovely. We've already heard the robin, do you have other wildlife coming in here?

Marta: We have a black bird as well and they try to sometimes nest in here. We had, on one occasion, a duck, a mallard from the lake below coming in here and happily swimming in our lake but we thought it's a bit too much and we encouraged them to go their own way. We sometimes get a cheeky squirrel but then again we try to encourage the squirrels to get out because, unfortunately, they will nibble on our plants and they will destroy some of our plants.

Jane: I can imagine. Tell me about this plant, Dioon spinulosum,

Marta: Dioon spinulosum is one of the oldest living plants in the earth, it comes from the dinosaur era.

Jane: It’s so cool.

Marta: This one doesn't come from… but the family…

Jane: No, obviously, yes, it's a really ancient plant and it's got these amazing serrated pinnate leaves on these fronds.

Marta: They are very sharp.

Jane: I bet.

Marta: They are very sharp, they're very difficult to prune because you have to have long sleeves and things like that. Over the pandemic it flowered.

Jane: Oh wow.

Marta: Males and females are separate flowers, so we found out that he's a male.

Jane: Okay, you don’t have a female?

Marta: No, we don't have a female but we have another one but we suspect it's a male as well, so we do not produce the seeds as such.

Jane: That's amazing.

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Jane: We'll return to my Barbican visit shortly but now it's time for Question of the Week which comes from Katja and concerns a trio of Kentia Palms. These quintessential Victorian Palms are quite something and lucky old Katja to have three of them. Katja is considering using Lechuza Pon in the substrate of her Kentia Palms, mixing that in with the regular substrate. Will it work? Well, I very much suspect it will Katja, Howea forsteriana, is a species of Palm that only comes from the tiny speck between Australia and New Zealand that is Lord Howe Island. I dedicated a whole chapter of my forthcoming book Legends of the Leaf to this plant. The speck? Well, basically, the island is made up of an ancient eroded volcano, so you can imagine the soil there is pretty volcanic and free draining. So, I think that adding the Lechuza Pon which, as we know, is a mix that includes lava and pumice would be a really good choice for these Palms.

If you remember back to my Lechuza episode, I'll stick a link to it in the show notes, there are different ways of using Pon and you don't have to use pure Pon, you can add it to your mix either using the 25% rule where it's a drainage level separated from the soil with a drainage barrier. The 50% rule where you've got the root ball covered with soil and then you've got Pon around that. I think there's also probably a third option which is you mix in handfuls of Pon with your substrate, when you're repotting, and it's spread throughout the mix, I think that would work equally well.

The great thing about this particular Palm is that it's tough, that's why it was really popular in the Victorian era and much beloved by Queen Victoria and it can cope with all kinds of abuse, but certainly adding some Pon to the mixture I would imagine is only going to make the plant happier. The reason why it's happy in our homes is because they're quite similar to the weather on Lord Howe Island, which I think it's defined as cool or warm subtropical. So temperatures are 20 to 25 centigrade in the summer and then down to about a minimum of 14 centigrade in the winter, that’s about 57 fahrenheit. So they live in similar conditions in their natural habitat and then, of course, in our homes we can offer them something pretty similar without too much effort. Because of where they live, often quite close to the sea in coastal parts of the island, because basically the whole island is coastal, they've evolved to deal with things like drought stress and shading from bigger trees and also salty air as well.

They're really fascinating plants, Kentias, and should be more widely grown. I can't wait to bring you loads more fascinating stuff about Kentia Palms in that chapter in the book which features everything from the Tree Lobster of Lord Howe Island to sympatric speciation, which is basically the enigma of the fact that two very similar Palm species had evolved on one very small island. In fact, the reason for that can be explained by the soil. More of that in the book but given that Kentias sit right on a volcanic island, I think a bit of Pon will do them no harm.

Thanks for your question Katja. If you've got a question for On The Ledge, please do drop me a line OnTheLedgepodcast@gmail.com and now I'm back in The Barbican Conservatory and we're heading to the special area reserved for cacti and succulents.

Jane: Where are we Marta?

Marta: So we are, what we call, an Arid house, where we keep all our cacti and succulents. So every cactus is a succulent but not every succulent is a cactus.

Jane: Yes and you've also got some orchids in here which are looking very fine and in flower right now. There are so many things in here that I absolutely love. Your Lepismium there is flowering, mine is also flowering, it's not quite as big as that but you've got lots of plants which cactus and succulent lovers will recognise but maybe haven't seen quite this large, because there are some really big specimens in here. This must be one of the favourite areas for people to visit because they're just so charismatic these plants, aren't they?

Marta: Yes, it is, talking to the public lots of people say the arid house is their favourite, unfortunately we had to keep it closed simply due to the restrictions that we just recently had because it's a quite enclosed and small space. Also, as I said before, there's lots of precious plants in here, all rare and endangered. They are quite an easy target for people but we try to grow them as much as we can for display hopefully in the future.

Jane: I'm just staring at this massive Crassula with these beefy, beefy stems and trunk. Is it Gollum?

Marta: It is, it's a Gollum version, so we've got three or four different Crassulas, so we've got your standard Money Trees here, Crassula ovata that just finished flowering. We've got the variegated version, the Hummel’s Sunset version, which is like a yellowy red variegation and also we've got the Miner, so a much better for your standard home of that version.

Jane: Yes, because they do get very large. That is, I don't know, 4 ft or 5 ft tall and it's just chunky, that is a chunk of a plant, I'm loving it.

Marta: It is, I'm 5’ 6”, so this is bigger than I am, so you can imagine.

Jane: Yes, it is and it's good to see what these plants turn into, I think that's one of the things that you're really getting from that. You've got lots of hanging baskets with beautiful Epiphyllums, Rhipsalis, a very impressive Sedum Burro's Tail. Is it difficult to water these hanging baskets? Have you got special equipment, please tell me you’ve got something?

Marta: You can see there's a pipe going on top and it's an irrigation system, so we can just water the hanging baskets, it's much easier. Everything else in the conservatory is watered by hand with the hoses, so we don't run around with little watering cans, as people imagine, in dungarees and a watering can.

Jane: Thank goodness!

Marta: We've got hoses and we water everything by hand because it's such a mixed and varied collection, the best computer is our brain, so we can adjust the watering to suit the needs of a day or temperatures and, obviously, to the plant itself.

Jane: How on earth do you avoid getting prickled to death when you're doing work on some of these really large columnar cacti? Is it a side effect of the job that you end up…?

Marta: It is, you get used to doing it, I think. Very often we try to put on long sleeves but you can imagine in the heights of summer it can be difficult. You sometimes get funny looks on the train or buses from people when you stick a hand out and they’re all scratched, but I think it's the side effect of the job.

Jane: Apart from in the very hottest days, it must be a delightful place to work? I'm just getting distracted by that huge Pereskia, that's amazing! I always think of it as the leafy cactus, or Rose Cactus is its common name apparently, but that is just… it looks like something out of a children's imagination of a cactus. It's got these huge areoles with these enormous spikes on this quite skinny stem and then the leaves on the top, it's just an incredible plant. Are there any particular favourites in here of yours, cacti that you particularly love? The non-spiky ones maybe?

Marta: Non-spikey ones. Probably the tiny Peyote, simply because it grows one centimetre a year in a good condition, so you can imagine how endangered they are if they grow so slow. Other than that, they are so lovely and they have so many shapes and forms and it's so difficult to pinpoint every single one. You look on the massive Echinocactus grusonii, Mother-in-law's chair, you can imagine why they called that.

Jane: I think mother-in-laws get a really bad rap from plants, don’t they?

Marta: They do and I don't understand that but lots of plants have some strange connotations to mother-in-laws. To all mother-in-laws, I don’t believe it’s true.

Jane: I guess the other name is Golden Barrel Cactus, they do look like barrels, yours are just enormous. I've got a tiny one of those and you do have to remember that's what it's going to turn into eventually, they are enormous.

Marta: It does, lots of those cacti were donated to us by cactus collectors over the years, simply because their collections were too big and they couldn't care for them. So they wanted for them to grow somewhere they would be looked after and, hopefully, we do them justice.

Jane: Yes, it's a lovely space to have filled with cacti and I'm sure it's glass everywhere, so the cacti are happy, they've got plenty of light in here. We didn't really talk about whether you have enough of plants at work or whether you have plants at home, do you?

Marta: I do have plants at home.

Jane: You're a glutton for punishment!

Marta: Yes, I do have lots of houseplants, I live in a flat. I don't have a balcony or a garden and so I do have a lot of houseplants at home. The only thing is with my houseplant is once you water this or you do all the jobs in here, you tend to choose your houseplants wisely, the ones that don't need a lot of attention or they are relatively easy going. You can forget about watering from time to time and they will still be lush and beautiful.

Jane: So what are your choices then, let us into your secrets?

Marta: So they will be orchids, basically, I'm a little bit of a person who buys the saddest plant on the shelf, the discarded ones: “Oh, I will rescue you,” and all that stuff. Your Pileas, Peperomias, your standard houseplants, even your Ficus elastica will do without any watering. So if you're worried about your houseplants going on holidays, I can guarantee you if you water them properly, once a week after a week’s holiday they will be absolutely fine. I've got some of the Caudex plants, so quite a few of them. My son started to collect some cacti and I'm dreading that for the passion to explode. I've got… I counted around 60 of them at home.

Jane: Okay, well it's obviously not enough time spent with plants. It's great, you're obviously passionate doing it at home and at work, so that must be a big tick. Well, it's absolutely glorious in here. I could just spend all day just staring at the plants in here and enjoying them because there are some wonderful things. I just keep thinking of the logistics for you of dealing with some of these huge Epiphyllums and Rhipsalis and I just salute you because it must be a real battle sometimes, repotting some of these hanging baskets.

Marta: Yes, we are actually bracing ourselves for the repotting season. You can see some of the Epiphyllums already have some flowers on them, so we let them flower this year and usually they flower around May time. So every single Epiphyllum is covered by these fantastic massive flowers, I'm talking the palm of your hand. Lots of vivid colours and once they start to fade we will repot them because we have some cuttings that we've propagated.

Jane: I’m just seeing some buds up on that one, this one right above us there's some buds coming.

Marta: They won't be thrown away though, we've moved probably to one of our levels in the good spots but they will need to be refreshed because some of them will get woody and tired over the years.

Jane: It's an interesting thing coming in here when you see these much more mature plants. We're used to seeing a teeny little tiny cactus or whatever and then when it starts to get some corking or some woodiness people panic and you have to say: “Well that's actually completely normal, this is what happens as they get bigger,” they don't stay pure green and this is a perfect example of how they change as they age.

Marta: Yes, so the corkiness as you said, or woodiness, it's two factors, sometimes due to the conditions that they grow in, so if it’s too moist they will protect themselves by producing those colours or corkiness. Over the years the stem, as you said, gets more woody and woody and that's how they will be in your natural habitats, you will travel to Canary Islands, Mexico, South Africa, you see them and they will be like that. Only the tops will be nice and fresh and green. I get asked sometimes: “Oh there's some dead leaves, the plants have not all their leaves removed and it's not perfectly manicured,” yes, because they are living objects, living plants, they're not like that in nature. We get used to seeing them in more artificial environments, where the Palms don't have their scales of dead leaves, they're just all manicured in the hotels or rows of streets but nature is completely different.

Jane: Yes, exactly and I think if the plant gets to a good age then it's got a few marks to show it.

Marta: Yes, they age just like we age, we show our marks, plants show their marks that shows how they basically go through their life.

Jane: Well, thank you so much for showing me this lovely space and I'm just going to be in here taking some deep breaths and taking some photos now. Thank you so much.

Marta: You're welcome.

[music]

Jane: I hope you enjoyed that tour around The Barbican Conservatory and if you want to check out some images, do visit the show notes at JanePerrone.com there you'll also find details of how to get your free tickets to The Barbican Conservatory and a list of the plants mentioned in this episode. That's all for this week's show, I shall be back next Friday. I hope your week is infused with chlorophyll and flooded with sunlight. Bye!

[music]

Jane: The music you heard in this week’s episode was Roll Jordan Roll by The Joy Drops, The Road We Used To Travel When We Were Young by Komiku and After the Flames by Josh Woodward. The ad music was Dill Pickles by the Heftone Banjo Orchestra. All tracks are licensed under Creative Commons, visit the show notes for details.

I visit the Barbican Conservatory in London and talk to head gardener Marta Lowcewicz about this incredible glasshouse. Plus I answer a question about a Kentia palm.

Visit the Barbican Conservatory

Admission is free but you must book in advance. Tickets are released online around two weeks in advance. Top tip from Marta - check on the day you want ot visit as some extra tickets are released on the day.

The Plant Ledger is here…

Sign up now to get the next edition of new email newsletter covering the UK houseplant scene and you’ll get my free guide to dealing with fungus gnats!

Check out the notes below as you listen…

Ficus benjamina trees at the Barbican Conservatory

Weeping fig trees grow tall in the Conservatory. Photograph: Max Colson.

  • The Barbican Conservatory is the second largest glasshouse in London after the Temperate House at Kew Gardens!

  • It was designed by the architects of the Barbican - Chamberlin, Powell and Bon - to disguise the fly tower, a concrete tower above the Barbican Theatre where the backdrops to performances are held. (You can watch a video about the flying system at the Barbican here.)

  • Temperatures are typical of a temperate climate rather than a tropical one: the temperature in the main glasshouse is kept to a minimum of 11C (52F), although the arid house is allowed to get down to 8C (46F) in winter.

  • The Conservatory is home to 1,500 species plant species, 300 of which are succulents, and many rare and endangered species including the pachycaul nettle Obetia ficifolia from Madagascar, and the peyote cactus, Lophophora williamsii from Mexico and southwestern Texas.

  • All the plants including the trees are planted in beds as the Conservatory is three floors up! The beds are 1.3m at their deepest point.

Marta Lowcewicz near a Sedum 'Burro's Tail'

Marta Lowcewicz in the arid house at the Barbican with a huge Sedum morganianum. Photograph: Jane Perrone.

Other plants we mention include….

  • Monstera deliciosa, the Swiss cheese plant, is one of the most photographed plants in the Conservatory.

  • Araucaria heterophylla, the Norfolk Island pine

  • Ficus benjamina, the weeping fig, has grown into a tall tree so it must be pruned annually.

  • The cast iron plant Aspidistra elatior is one of Marta’s favourites.

  • Tradescantia pallida 'Purpurea' is planted in a windowbox trailing from a balcony.

  • Dioon spinulosum, the giant dioon, flowered over the pandemic which allowed staff to confirm it as a male - there is no female plant at the Conservatory to sexually reproduce with!

  • The Arid House is home to a really huge Sedum morganianum, the burro’s tail succulent.

  • There are several huge jade trees, including a Crassula ovata ‘Gollum’.

  • Some of the succulents have been donated by growers who ran out of room, including several Echinocactus grusonii, the golden barrel cactus.

  • The cactus with the huge spines and areoles as well as leaves was a Pereskia.

Check out more photos from the Conservatory in the gallery below: click images to get a closer look. All images below are by Jane Perrone.

QUESTION OF THE WEEK
Katja wanted to know whether a trio of Kentia palms would benefit from adding Lechuza Pon to the substrate. Howea forsteriana comes from Lord Howe Island, a speck of ancient eroded volcano sited in the ocean between Australia and New Zealand. So I suspect that adding Pon - which contains lava and pumice - will certainly do no harm to a plant that is used to living in soil with a volcanic element.

Although we think of this palm as a classic Victorian plant, it evolved to cope with life on this tiny cool tropical island, dealing with drought stress, shade from taller trees and salty air, so it does well in our homes.

Check out my Lechuza Pon episode for guidance on the 25% and 50% options for combining Pon with organic potting mix. (Intrigued by the sound of the tree lobster? Find out more.)

Want to ask me a question? Email ontheledgepodcast@gmail.com. The more information you can include, the better - pictures of your plant, details of your location and how long you have had the plant are always useful to help solve your issue


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HOW TO SUPPORT ON THE LEDGE

Contributions from On The Ledge listeners help to pay for all the things that have made the show possible over the last few years: equipment, travel expenses, editing, admin support and transcription.

Want to make a one-off donation? You can do that through my ko-fi.com page, or via Paypal.

Want to make a regular donation? Join the On The Ledge community on Patreon! Whether you can only spare a dollar or a pound, or want to make a bigger commitment, there’s something for you: see all the tiers and sign up for Patreon here.

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If you like the idea of supporting On The Ledge on a regular basis but don't know what Patreon's all about, check out the FAQ here: if you still have questions, leave a comment or email me - ontheledgepodcast@gmail.com. If you're already supporting others via Patreon, just click here to set up your rewards!

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CREDITS

This week's show featured the tracks Dill Pickles by the Heftone Banjo Orchestra, Roll Jordan Roll by the Joy Drops, The Road We Use To Travel When We Were Kids by Komiku and After The Flames by Josh Woodward.