From www.awaytogarden.com — ‘fat’ houseplants: caudiciforms and more
IF ANOTHER HOUSEPLANT dropped all its leaves for several months each year, you’d think you killed it. But with some of Ken Druse‘s and my favorite indoor companions, from Bowiea to Jatropha and more, a regular dormant period is just part of their lifecycle. And even if all their leaves are missing in action for a while, these curious plants’ sculptural, swollen bases are still there to admire—water- and nutrient- filled structures that are also the plant’s secret to survival.
Ken and I are fans of what are sometimes called fat plants—some of which are technically classified as caudificorm (having a caudex at the base), and on a recent podcast, we talked about these collectible curiosities (like my Pseudobombax ellipticum, whoe caudex is in the photo above).
Ken is the author of 20 garden books, and gardens extensively, outdoors and indoors, in New Jersey. He’s also my co-host of the Virtual Garden Club series of online classes the last several years.
Read along as you listen to the March 3, 2025 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify (and browse my archive of podcasts here).
‘fat’ houseplants, with ken druse
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Margaret Roach: I apologize if by talking about these plants with you the other day on the phone, just innocently, before we decided to do this podcast if I caused any binge searching on the internet or binge shopping.
Ken Druse: Oh, no. And don’t forget the rabbit hole.
Margaret: Ken’s going down a rabbit hole again. Yeah. So are there any sort of sleeping houseplants, sort of sculptural sleeping houseplants over there in New Jersey at the moment?
Ken: At the moment? Well, there’s two Ficus, and Ficus are figs. And I’ve got one that’s Ficus palmeri and another one that’s Ficus petiolaris [above at Ken’s]. And they have swollen bases, which is what we’re pretty much talking about. There’s some plants that have, well, they have tuberosa in their species name, so that might be ones to think about. And obesa [laughter].
The Ficus have a few leaves left; in the summer, they have leaves. Now they’re sleeping, and I guess in their native habitat, when it really gets dry, they would lose their leaves completely. And that really tips you off on how to care for them.
They don’t really want food or water in the winter. Well, hardly any houseplants want food, but you know what I mean. And it’s incredible that they’re houseplants, because when I think of these plants, some of them would be really hard to grow because I don’t live in South Africa in the desert.
Margaret: Or Mexico or whatever. And so not all the houseplants… First of all, they’re not houseplant in nature [laughter]. They’re not houseplants, but not all these plants that we use as houseplant that I described in the introduction, these ones that you were just talking about with these swollen bases, they’re not all related. And technically the storage organ that’s filled with water and other resources, they evolved that zillions of years ago in their homelands, which are usually desert-like, to get through an annual drought period.
And in some of these plants, it’s technically called a caudex and they’re called caudiciform plants. And in some, it could just be a bulb. But it’s a place to store the goods to keep you alive when you can’t do photosynthesis and you there’s going to be no water to take up through your roots and so on and so forth. So a survival tactic.
Ken: There’s so many plants that we grow that up from tubers, and this is tubers that grow above the ground.
Margaret: Not technically tubers, but looks like. Yeah, and that’s the thing is the geophytes, as we call bulbs and corns and tubers and the things that hide underground—your daffodils, they come up, they make some foliage, they make flowers, eventually they wither and they disappear for most of the year, half the year at least. This is sort of that type of thing, but the storage organ is above ground.
Ken: And crazy wild. And that’s why we want to grow them. I guess some people might not think they’re beautiful. I do. And they’re fascinating and well, as you said in the beginning, I want them all. [Laughter.]
Margaret: Right. And the fun thing is that you can find these sort of plants with swollen bases in many, many different genera of plants, and many different groups of plants as well. And so you can do it strictly on looks. Again, it’s not like, oh, I’m a collector of Primula. Oh, I’m a collector of, do you know what I mean?
Ken: Begonia.
Margaret: Yeah, it’s wider than that. And you can just do it on looks and have fun with it. And some of them in their native habitat—like I have one that’s meant to be a tree. It’s called the shaving brush tree [above], Pseudobombax ellipticum. And when I got it, I thought it was Bombax ellipticum, but apparently it’s not. But whatever [laughter]—the name thing, right?
And I guess it’s supposed to be… It’s from southern Mexico and Central America, and it’s a deciduous tree. It sheds its leaves in nature seasonally there during the dry winter season, and so in my house it does that, too [laughter]. And it’s been in a pot for 30-something years, so it’s not a tree, and I don’t get flowers. I probably could if I were doing something better. But it’s been with me forever and I love it. And it just tells me when it wants to go to sleep in the fall sometime. The leaves just start to discolor a little, and I right away back off on the watering, and it sleeps through the winter. So it’s got this big sort of green and brown gnarly structure at the base that I just love and all these different branches coming up out of it and off it. So it’s fun, but it ain’t no tree in my living room.
Ken: You’re making me think of the Dioscorea.
Margaret: Exactly, exactly.
Ken: We’ve talked about those. I grew Dioscorea elephantipes, can you imagine? Elephant-types. And they look like turtles sort of for most of the year. And then just like the Boweia, all of a sudden up shoots this vine, and for half the year it has a vine with sort of lovely green, heart-shaped leaves, and it can climb like, oh, I don’t know, 7, 8 feet. And then the leaves start to yellow and I stop watering. And then I’ve got this fantastic turtle in a pot.
Margaret: Right, a potted turtle [laughter].
Ken: And they can get really big, I mean, well, in their native habitat, they can get 7 feet across and weigh, I don’t know, 100 pounds maybe or something, because they’re filled with water, and that’s the whole thing. They’re storing their moisture and nutrients in this sleeping thing. Do you remember when we used to put sweet potatoes in a glass of water-
Margaret: Yes.
Ken: …Halfway up, and then we’d get a vine and then it would dive in. Well, it’s exactly the same thing.
Margaret: Yeah. So you just said boa when you were describing that, and boa is one that’s not a quad X, not a quad form plant, technically speaking, doesn’t have a swollen stem. It’s a bulb that’s above ground or actually a pile of bulbs, multiple bulbs, like a cluster of them. And I think, do you have a Boweia [below, at Margaret’s] also growing at your house?
Ken: I’ve had Boweia, God, since I was a child.
Margaret: So for decades, and everyone I’ve ever gifted one to or whatever or turned anyone on to, it becomes their pet. It’s their little sweet pet. It’s this cluster of, they call it climbing onion; it’s not an onion, but climbing onion. And I think it’s related to hyacinths actually. And yeah, it’s crazy. And it’s like from tropical and Southern Africa, and it puts up this twisting vine-looking thing. And at some point, there’s tiny little green and white flowers.
Ken: They look like spaceships. I mean, they’re really tiny, like a fingernail size or smaller, and they’re sort of like stars. I think they look like spaceships.
Margaret: And when it wants to go to sleep, it says, Margaret, “I’m yellowing.” The vines are going to yellow. And, “Stop watering me.” You know what I mean? And again, mine—and I must just sound like the worst plant parent in the world because that shaving brush tree, that Pseudobombax, has been in the same pot for decades. And the Bowiea similarly has been in the same pot for decades. And in kind of a sandy mix; I grow these in a sandy kind of medium, like a cactus soil.
Ken: Almost all of these want really good drainage, all of them.
Margaret: But it doesn’t care; it’s self-sufficient or something [laughter]. It’s the weirdest thing. And it was one bulb, one green bulb.
Ken: I was just thinking that they all start, I got mine as one bulb-
Margaret: Like from Logee’s Nursery or something?
Ken: Then at some point it starts to split and very happily, and then you have three, and then you have more, then you maybe give one away. But it’s funny the way they split, but they ultimately end up being perfectly spherical.
Margaret: But you’ve seen bulbs, like when you’ve taken bulbs out of the ground, or even when you’ve sometimes bought bulbs and they have a little, almost like a baby bulb hanging onto the side of the older bulb, and you say split, it’s like that. It’s like they grow in a cluster, do you know what I mean? They’re tightly connected to each other and you can kind of break them apart. But yeah, so it’s like an above-ground bulb, and they’re bright green with a papery, thin papery tan husk kind of over the bulb at certain times. Some people I think peel that off.
Ken: I peel that. We like the shiny green. It’s very thin, this papery thing.
Margaret: But the Bowiea is a great gateway plant for these kind of crazy plants. It’s super-easy. It’s available. You get a little one, and then again, you’re hooked. And it’s so fun. And the vine, it’s got its own personality altogether. It’s not just a vine. I don’t even know how to say what it is [laughter], and I don’t really know what the technical parts are, but it’s-
Ken: Like a wire stem.
Margaret: With froth coming off it or something. Right. It’s like it’s really beautiful. I have, over the pot of mine, I have a tripod of three thin bamboos tied at the top, like a tripod. And so it just twists around those and makes this tent over the cluster of bulbs. The vine makes a tent of this green froth in season. But yeah, it’s fun.
Ken: I don’t want to get too technical, but have you ever propagated it? [Above, the process under way at Ken’s.]
Margaret: I haven’t, no.
Ken: You can take a little piece of the scale, like an onion. It has layers. You can cut off a little piece of that, I mean really little, and put it on some barely moist medium. And from that little edge, the cut edge, things will grow, and they’re like peas, like garden peas, and those are new plants.
Margaret: Right on that piece of scale at the soil surface that you stuck it in, you’ll get these little peas. And those are your new bulbs.
Ken: Yeah. You hardly put it in. You sort of put it on, and it’s fast. You’d be surprised.
Margaret: Any of the other ones—you mentioned you were growing some other ones?
Ken: Well, I have a few that don’t lose their leaves completely,
Margaret: But they have the caudex?
Ken: The swollen base.
Margaret: O.K.
Ken: My Beaucarnea, which is a lot of people grow, the ponytail palm, and they get really big in Florida, but we’re not in Florida outdoors. But I have a Beaucarnea recurvata, and it might be ‘Variegata,’ and has beautiful variegated leaves and that big swollen base [above]. And I’ve had that when I think how old we are [laughter].
Margaret: We’re not; actually I’m counting backwards now [laughter]. Is that the one? It’s gold and green variegated. Is it green and white or green and gold?
Ken: Well, creamy.
Margaret: Creamy, yeah. I sort of remember seeing pictures of it.
Ken: And a lot of these plants are really slow, and as houseplants, I think in their habitat, they may not be quite so slow, but when you stick anything in a pot, it sort of bonsais it. It keeps them kind of small and they’re kind of slow, but that’s good. I don’t have room for an 8-foot tree [laughter].
Margaret: Right. Well, and the one I mentioned earlier, the Pseudobombax, the shaving brush tree, supposedly in its native habitat in Central America or whatever, or southern Mexico, apparently it gets to 60 feet tall [laughter].
Ken: Right.
Margaret: And 4 feet wide at the base.
Ken: And people get water out of it, when it doesn’t rain. Oh, wow.
Margaret: So I mean, what we’re basically doing, I guess, is what I would want to say is, which is a word that we all are familiar with, is we’re sort of bonsai-ing them just by keeping them in a pot. We’re telling them to stay small.
Ken: Yeah. We’re constricting them.
Margaret: Exactly. Any others?
Ken: All the love that we give them, maybe makes up for the torture [laughter]. It sounds like torture.
Margaret: Someone a year or two ago gave me another one. Knowing that I like these kind of plants, they gave me a Jatropha and it’s, they call it the Buddha belly plant [laughter].
Ken: Perfect.
Margaret: And I guess it’s like some tropical succulent, I guess it would be shrubby in its native habitat, maybe 6 or 8 feet tall, and I think it’s from Nicaragua and Mexico and so forth. But yeah, it stays relatively small. I mean, I guess eventually it could get to be a couple feet tall in the container if you allowed it to, but I only have a little one right now. But it’s also fun, and it’s been asleep for months. And it just told me when; it indicated when it was time.
Ken: You’re reminding me that maybe the biggest family or genus of these kinds of plants are Pachypodium. And there’s so many—a lot of them have thorns, but a lot of them are little fat things with little arms and a few leaves and maybe some flowers. But I don’t know if you know what desert rose is? Adenium. [Above, Pachypodium lamerei from Paradise Found Nursery.]
Margaret: Right, right. I was almost going to say it. Adenium.
Ken: I can’t grow that. I just don’t have enough sun. But that outdoors, in the right location, people grow them for their flowers. They wake up in the spring and just bloom and bloom with lots of flowers in all different colors. They’ve been hybridized and selected. We don’t see them very often. But if you live in Arizona, you would know what a desert rose is.
Margaret: Right. A lot of these are at least Zone 9, but probably even Zone 10, etc. plants. Yeah. The Jatropha is supposed to get flowers, too, I think; red flowers or something. I mean, I have a long way to go if that’s ever going to happen. But when it had leaves last summer they were almost fig-shaped. They were kind of big, lobed.
So it was kind of nice. It had nice foliage as well, which was, you mentioned the Dioscorea. Now that’s technically a yam, right? We have native Dioscorea here, like Dioscorea villosa, that a little tuber-y kind of thing that grows under the ground or at ground level, and a vine and so forth.
Ken: Yeah. Well, you’re reminding me of something. Many, many years ago, I found a Dioscorea elephantipes in the trash in SoHo, and it was probably almost 2 feet across. And I think that probably somebody had it as a decorator plant. It was definitely wild-collected. I don’t know. It could have been 20 or 30 years old. And they thought, oh, it lost its leaves. It’s dead. I’ll throw it out. And I rescued it, but unfortunately it had some rot and I had it for about two years before it finally kicked the bucket. But if you can imagine 2 feet across Incredible. That’s a really good genus for what we’re talking about for these swollen babies. Weird but lovable plants. [Laughter.] [Dioscorea elephantipes from Wikimedia, above.]
Margaret: And what I also love is that what you were just describing, the base, I think they look great in kind of a low pot. It doesn’t have to be huge, even though it was a wide thing that you were just talking about, it doesn’t have to be in a 3-foot-tall pot or something. Do you know what I mean? I don’t know what you have something like that in, but-
Ken: It was a challenge.
Margaret: Yeah, the big, I have probably about nine of the bulbs of the Bowie now in this same pot they’ve been in forever. And it’s a low dish. It’s a terracotta dish. That’s one other thing: I wouldn’t grow any of these in a plastic pot. I would grow them in glazed terracotta, I think, for the good wicking away of the water. I don’t think you want the soil to stay moist even during the active growing season. Do you agree?
Ken: Definitely. And maybe protect it from getting too much rain where we live.
Margaret: You mean if they’re outside?
Ken: In the summer, right, they could rot.
Margaret: Now. See, that’s interesting. So you bring yours outside?
Ken: I bring everything outside.
Margaret: So here’s my paranoia. Just one of my many examples of paranoia. Because years ago I had a horrible incident where I had a cylindrical Sansevieria, Sansevieria cylindrica, the one with the round foliage that is pointed at the tips, its cylindrical foliage. And I loved that plant and I had it for a long time. It was really beautiful. It was kind of variegated. And we had a hailstorm and it just got pitted like crazy, really disfigured. And so I’ve never brought my Boweia or my Pseudobombax—I don’t bring any of these guys outside because I’m afraid of catastrophe.
Ken: Yeah.
Margaret: So they stay in, these are my only plants that stay in. Actually, that’s not true; the Clivia stay in, too, for the same reason because they have that very sort of thick evergreen foliage. And that also could get very damaged by aberrant weather.
Ken: Well, there’s very few things that I bring outside that go in full sun. But as you’re saying this, I don’t have any south facing window. I’ve never had a south-facing window, which would make it so much easier to grow so many things. Not the Clivia necessarily, but things like we’re talking about really. When they’re in active growth, they really need sun.
Margaret: They want a lot of light.
Ken: And indoors, I don’t have the sun, so a lot of the plants really look tired. By March, actually the end of in March, they look really great, and then they collapse. They all fail. They just can’t hold on any longer. And then they go outside and they sort of come back. So I really have to do that. I don’t have the south space.
Margaret: And I would like to, but as I said, I’m just spooked. I was spooked by having that plant so badly damaged, and it would take 10 years to outgrow it.
Ken: Well, I have a big porch and some covered areas, so they get the nice air. I end up having to still water them because a lot of them are undercover.
Margaret: But they’re safe from hail.
Ken: And I don’t have hail, like you have hail.
Margaret: Yeah, usually it’s like once a year or something, but boy, it’s dastardly. I just want to talk about in your…we won’t call it shopping, we’ll call it searching…this last week, I know I was looking around and I found some websites besides Logee’s, which has a number of caudiciform plants as well as the Bowiea with its bulbs. I found the sort of motherlode, it seems, at a nursery in Florida called Paradise Found. And they even have specimen-size plants for quite a hefty price, some of them.
Ken: A thousand.
Margaret: They have small ones too. But you could get one that’s already, because you were saying they’re slow-growing, you could get one that’s already like a full-on sculpture. But at any rate, and then another one called Planet Desert, which has a number as well of caudiciform plants. Did you find any others? [Below, the Pseudobombax in the living room at Margaret’s.]
Ken: I found lots of things and I found, I don’t know if I can remember the name, but there’s a caudex site that this person has whose name is B-I-H-R-M-A-N-N, and I don’t even know if it’s in the United States, but if you Google caudex or caudiciform, it’s one of the things that’ll come up. It’s not a nursery. They don’t have things for sale, but they hundreds of plants.
Margaret: Like a reference.
Ken: I just want to warn people. You may see a fabulous picture of a 30-year-old plant, but what you’re going to get for $7 in the mail is going to be a little seedling. And sometimes be careful. You might be getting seeds, but I was surprised. Even Amazon has some for sale.
Margaret: Well, and Etsy and places like that. But I prefer to shop at somewhere like Logee’s or Paradise Found or Planet Desert.
Ken: Remember that you’re getting a young plant, that’s all.
Margaret: Yeah. And some of them say, it’ll say, this is a 2-inch pot, this price, it’s a 3-inch pot, this price, it’s a 6-inch pot… They may have different sizes. So you just have to be mindful of that.
Ken: It would be great if some of these places showed you exactly a picture of what you’re going to get.
Margaret: Well, we’ve squandered another podcast. Thank you, Ken. And I will not accept the bill for your shopping binge when you’re done, even though it’s my fault. So thank you. Fun to talk about fat plants with you, and I’ll talk to you again soon.
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