Unfinished business: Stapelia (Orbea) variegata

I noted in the previous Stapelia/Orbea post that there were several more buds on the plant, which was a little worrisome considering the smell. One flower was tolerable -- we could only smell it if we were standing close -- but it looked like there was going to come a day when several flowers would bloom at once.

Well. That day arrived, but before it did, the husband added more plant shelves above the kitchen sink. And the S. variegata was one of the plants that wound up on the new shelves, when it only had one flower open.

This was nice, to a point, because it meant that every time I was near the sink, I could spend some time looking at the flower. It's pretty striking, and the smell was only intermittently detectable, so, you know, no real problem. Then a second flower opened, which was a little harder to ignore.

And then on 13 October, a third flower opened, at which point the husband told me that something must be done.

So for those of you wondering how bad the smell is, I have an answer. It's somewhere between one-half and one-third of revolting.¹

I elected to cut the flowers off, because they last too long to wait for one of them to drop and it's too cold to move the plant outside until the flowers are done. So here they are.

But then, a tangent:

I bite my nails. Always have. I would sort of prefer not to, in that way that you can dislike something but not care enough to do anything about it. I'm also not necessarily consciously aware that I'm doing it. Anyway. So I took the above photos and everything, came inside to upload them to the computer, and then all of a sudden GAH! WHAT IS THIS HORRIBLE, HORRIBLE TASTE AND WHY IS IT IN MY MOUTH?

Apparently I had gotten some sap on my fingers while cutting the flowers off. The good news is that the sap doesn't taste like the flowers smell; the bad news is that it's intensely bitter.

Oh my god. This can't be good. Is it poisonous? Am I going to die?

So I ran to Google, as one does. This turned up a paper from 1981 in which the chemical hordenine (N,N-dimethyltyramine) was isolated from Stapelia gigantea. It's not clear that hordenine is responsible for the taste -- I found a number of references on Google linking hordenine to a bitter taste, but most of them were describing combinations of different things, not pure hordenine.

In any case. Hordenine is not particularly toxic, and stapeliads in general aren't either, which is good news.² There's some compelling anecdotal evidence that it wasn't harmful too, given that all of this happened a week ago and I'm not dead. But, you know. This is the sort of thing I like checking into regardless. And as a bonus, it answers my questions about how stapeliads manage to get by in their natural habitat without toxins or thorns.

-

¹ For the record, neither of us had a problem with the third flower until the husband had to spend some time at the sink doing dishes. Had it not been for the dishes, we might have been able to cohabit with three flowers just fine: I only ever noticed the smell when I was within a couple feet of the blooms. So a single S. variegata flowers has a smell measured at 0.4±0.3 revoltings.
² The very worst-case lethal dose quoted for an animal at Wikipedia (113.5 mg hordenine/kg body weight, for mice), scaled up to my size, multiplied out by the amount of hordenine in Stapelia gigantea (0.024% by weight of fresh plants), suggests that in the very worst-case scenario, if it were as toxic to me as it is to mice, I would have to consume something like half my body weight of the plant to get a lethal dose. And it's possible that the animal model that applies is not mice, but dogs, in which case the lethal dose is 2 g / kg, and I would have to eat 700 kg / 1500 lb. of fresh Stapelia in order to die from it.
It is difficult to imagine a situation in which I would eat three-quarters of a ton of Stapelia.
These numbers are, of course, all wildly speculative -- I don't know if S. variegata has the same concentration of hordenine as S. gigantea, I don't know what the lethal dose for humans is, I don't know if there might be something way more dangerous in the plant that would kill me long before the hordenine ever did, etc. But at least as far as this one particular chemical is concerned, I feel pretty untroubled.

Pretty pictures: Paphiopedilum Winston Churchill 'Indomitable'

This is just depressing. I would totally try to grow Paphiopedilums if I thought there was a chance they wouldn't die on me.


Actually "depressing" is probably not the word. I'm not sad, I'm uncomfortably envious. Which is an entirely different feeling.


I was fortunate to find a nice write-up of this particular cross elsewhere on the internet, so instead of saying more, I'll just direct interested persons to this page.

A Final Six Plants I'm Not Currently Mad At (Po through Z)

And now, the thrilling conclusion of the plants-I'm-not-currently-mad-at series. (A-G is here; H-Pn is here.)


1. Podocarpus macrophyllus

Podocarpus has died several times under my care already, and may again, but we're getting along for the moment. This one's my longest-lived yet. (Two and a half years!)

Date: September 2012.
Pot size: 4.5" / 11.5 cm?
The problem is always watering: let a Podocarpus get too dry, and you will have an unhappy Podocarpus. My solution to this has been to keep mine in a larger pot than I normally would (I repotted shortly after the above photo was taken, in fact), and to water every time its turn comes around in the watering cycle (i.e. every two weeks), whether it feels dry or not.¹

Date: April 2010.
Pot size: 4" / 10 cm.
Otherwise, not that big of a deal. I have a faint recollection of mealybugs or scale in the recent past, but I'm not sure if that's something that actually happened or just something I was dreading really vividly. It's been happy with artificial light so far, and has lived in the basement since its arrival, so the cooler temperature and higher humidity down there may be contributing to its non-death.

In any case, this is a plant that really shouldn't be working out for me, but it nevertheless is. At the moment. We'll see how that goes.


2. Polyscias fruticosa

As nervous as I was about buying Polyscias fruticosa, it's turned out to be a really reliable, good plant. They have a reputation for being temperamental, though this is probably more about them preferring consistency. Don't move it around a lot, and give it dependable water, and it should be fine.

Date: September 2012.
Pot size: 12" / 31 cm.
They're also surprisingly fast growers, when they feel like it. This plant has at least tripled in height in the three and a half years it's lived here. (I'm actually starting to worry that it might outgrow its spot!)

Date: May 2010?
Pot size: 6" / 15 cm.
I've had it in an east window for at least a couple years. It's been getting water every two weeks, plus a generous amount of fertilizer (year-round), but that's going to have to change, since I moved it into a larger pot a month ago. Watering will probably be more like once a month now.

It's never had any pests, and defoliated dramatically only once, this last summer. I think that was because it had gotten pretty rootbound, and was drying out too quickly, though it's also possible that the top leaves had just become so abundant that the leaves at the bottom were getting shaded out. Only the bottom leaves dropped, and not terribly many of them.


3. Rhapis excelsa

Rhapis excelsa is exactly the kind of plant I'm wanting to spotlight with these posts. I all but forget that I have it, because it never does anything terribly dramatic. It doesn't even need watering as often as most of the plants. It doesn't bloom, it grows really slowly, it holds on to its leaves, it suckers sluggishly -- there's really no reason to ever notice it. It even looks pretty much the same now as it did when I first got it:

Date: September 2012.
Pot size: 8" / 20 cm.
Date: March 2008.
Pot size: 6" / 15 cm.
At the same time, though, this is actually what a lot of people are looking for in a houseplant.² And even if it's not six times the size it used to be, there's a lot to be said for a plant that will just mind its own business and grow without getting bugs or requiring pruning or whatever.

The only complaint I have about Rhapis is that the leaf tips used to burn on me. They've stopped, since the plant got relocated to a cooler, darker spot, but it's not clear whether the change in temperature and light fixed the tip-burn problem or if it was something else entirely.³ Presently, it's in the basement, on the floor, where it gets heavily filtered light from some of the shop lights (though it doesn't have its own shop light) and some indirect sun, on the days when we have sun. I water it about every 4 or 6 weeks, and fertilize lightly year-round. I've yet to see any pests on it. I would love, love, love to propagate R. excelsa, but it grows so slowly, and propagation is so uncertain, that I haven't been willing to take the gamble yet.


4. Stapelia gigantea

S. gigantea is another plant like Plectranthus verticillatus, that's gotten smaller since I've had it; in this case, the reduction occurred because I cut off a big chunk of it for cuttings. (If I remember correctly, all the cuttings were successful. They're more wrinkled than the parent, and floppier, which is worrisome, but all are still alive, and most are now producing new growth.)

Date: September 2012.
Pot size: 6" / 15 cm.
The flowers are certainly interesting, though not necessarily the main thing I like about the plant. It scores points with me mostly for its tactile qualities, not so much its appearance (though the appearance is cool) or the flowers' smell (which is in fact unpleasant, though not as terrible as I'd been led to believe it would be). That, and it's easy to grow.

Date: September 2009.
Pot size: 6" / 15 cm.
My plant has been in a west window since I've owned it, not counting a brief period when it first arrived and I had it outside. (A bad idea: it burned.⁴) It would probably prefer a bit more light than that, but that's as good as I can do, and it seems to be able to get by on that. The cuttings are all downstairs under artificial light, which is even less bright than a west window, and they do okay, though it's worth noting that they aren't growing very fast.

The parent plant gets watered every time the watering cycle comes around, every two weeks; the cuttings get water more like every three or four weeks, but it's colder in the basement, and they aren't getting as much light, and they're in plastic pots, so that makes sense. I fertilize year-round. Sources elsewhere on the internet tell me not to let the temperature go below about 50-55F (10-13C), but neither the plant room nor the basement normally get that cold, so temperature and humidity aren't much of an issue. There have never been any pest problems; I've been watching for scale lately (because the cuttings are in that neighborhood of the basement), but so far I haven't seen any.


5. Stenocereus thurberi

Stenocereus thurberi was one of the plants I was offering for sale in the spring this year, because even though I liked the look of it, I didn't seem to have enough light to convince it to grow. Nobody was interested, though, so when I ended the plant-selling, the S. thurberi went outside, and once it was out there, it did produce some new growth.

Date: September 2012.
Pot size: 4" / 10 cm.
It's not dramatic new growth, of course. You would be forgiven for not noticing that the two pictures were different. But the top two or three areoles on each rib above is new growth as of this summer, and I've had the plant for almost three years. So it's a big deal to me.

Date: December 2009.
Pot size: 3" / 7.5 cm (along diagonal).
Other than its unreasonably high demand for light, S. thurberi has been easy enough to grow indoors: I try to keep it drier and reduce fertilizer in the winter, though I still water about every 4-6 weeks.

I suppose it's a little odd to praise a plant for not growing, but that's basically what I'm doing here: I've thrown out cacti that grew while not getting enough light,⁵ because the new growth is small, pale, and weak, and even when given better conditions afterward, plants don't necessarily fill in the spindly growth.⁶ So it's actually good if a plant refuses to grow for three years because it doesn't have enough light. Hopefully it won't keep growing this winter out of some misguided biological momentum or something.


6. Zamia furfuracea (?)

I repotted Z. furfuracea (or whatever it is⁷) in August, because it had been in the same 4-inch (10 cm) clay pot for a few years. It turned out that it did need to be repotted, but it's also lost a few leaves since then, which is something it basically never did before. It's also growing much larger new leaves now, so it's fine: the point is just that after a long period of being a good, stable plant for me, it's starting to undergo some Changes, and we don't yet know for sure how that's going to turn out.

Date: September 2012.
Pot size: 6" / 15 cm.
That said, though, I have no complaints with it so far. It's been fine close to an east window. It used to get watered every two weeks; I think so far I've continued to do that, post-repotting, but it may slow down to every four weeks in the winter, depending on how quickly it seems to be drying out. Neither temperature nor humidity are likely to be an issue to someone growing it indoors, and I've never had pest problems on mine.⁸

Date: October 2009.
Pot size: 4" / 10 cm.

Also relatively non-upsetting:

Sansevieria cylindrica
Sansevieria hargesiana
Scindapsus pictus
Selenicereus chrysocardium
Stenocereus pruinosus
Stromanthe sanguinea 'Triostar'
Tradescantia spathacea
Vriesea imperialis

-

¹ Is it possible to overwater a Podocarpus? Probably. I have one houseplant book that says they're prone to root rot if they're kept too wet or left to stand in water. It's not something I've ever seen personally, though.
² My recollection, from the garden center days, is that the houseplant every customer is looking for:
• has large, shiny, mostly-green leaves, with optional variegation,
• needs almost no light at all,
• produces huge flowers, year-round, in any shade of any color desired,
• is pleasantly- but not overpoweringly-scented,
• never needs fertilizer or repotting,
• is nontoxic to pets and children,
• and will grow to the height of exactly six feet (1.8 m) tall and then stop getting taller.
It takes a few months, but one does eventually get used to disappointing the customers.
³ The old spot was also in the basement, so things like temperature and humidity should have been more or less the same; the main difference between the two situations is that the first location had a shop light directly over the plant. I'm also fertilizing more now, but it would be weird if that was responsible: ordinarily if there's a tip-burn problem on a plant, more fertilizer will make it worse, not better.
⁴ They can, of course, grow outside in the sun: I just didn't try as hard as I could have to acclimate it gradually. It had most likely been growing inside on someone's windowsill before they brought it to the consignment store, so it would have been accustomed to lower light.
⁵ Specifically: Parodia microsperma and Echinocactus grusonii.
⁶ Some do, some don't: I have some mildly etiolated Myrtillocactus geometrizans that grew some weak new growth after arriving here, but they spent the summer outside this year and managed to fill in somewhat. They still don't look quite right: the newest growth is disproportionately big compared to the growth that immediately preceded it --

-- but the stems also thickened up a little bit, enough so that I'm optimistic that the plants will even themselves out eventually.
⁷ I'm positive that it's a Zamia; I just don't know which one.
⁸ I know they can get scale, though: when I worked at the garden center, we threw out a batch of Zamias (not necessarily the same species as mine) because they developed a bad scale infestation. Which was depressing: up to that point, I had been considering buying one of them for myself.