Wednesday, August 10, 2011

Random plant event: Huernia zebrina

I got a Huernia zebrina earlier this summer. When it arrived, it had a flower bud on it, but it dropped the bud within a few days, presumably as a result of the travel. Disappointing, but not unexpected.

I noticed last week that there was a bud developing again, and on Sunday I saw it open for the first time. This isn't as open as it will get, but it's as open as it got on Sunday.

I didn't detect any smell, though I suppose that doesn't mean there wasn't one. Googling turned up a few claims of an "intensely fetid odor" and about the same number claiming no odor at all. I assume this means one of three things: either 1) odor varies from one specimen to the next, 2) odor varies according to the development of the plant, with some stages being less smelly than others, or 3) people are lazy, and will spout off about the odor of plants they've never actually grown or smelled. My personal guess, based on extensive direct observation of human beings and limited direct observation of Huernia zebrina, is that it's probably #3.

The color is not quite what I was expecting, either -- photos on-line are a lot more dramatically-colored than this. I'm assuming this is because the flower isn't fully developed yet (you can see in the above pictures that it hadn't yet opened all the way). There will be a follow-up post if I see a dramatic change in the appearance or smell.


Diana said...

It could also be that some people have the ability to smell the flower and others do not. The ability to smell a few types of smells is genetic and if you don't have the gene for that smell you can't smell it.

Case in point: Bradford Pears. I can smell them and they are rancid. Most people do not have the ability to smell them and so think they are delightful trees.

Since Bradford Pears smell of rotting meat and this cactus supposedly also has a rancid odor it is possible that the same chemical is responsible for the smell and therefore only people who can smell Bradford Pears could smell your cactus.

Or it may be that people mistake the flower smell for the garbage needing to be taken out.

Long Haired Lady Rider said...

OK Diana, THAT is fascinating!

I was thinking that there could be two similar species, or two different collections of the same species, one with smell and vivid coloration, and one without.

Paul said...

Screwy olfactory receptors aside, I've never had a fetid smell off this plant, but the flowers DID have a deeper, scab-like color. They also seem to die shortly after they flower unless they're in a large clump; but that could be heat related (we keep ours outside).

mr_subjunctive said...


Well, I know from my personal experience with Freesias that it's possible to miss a smell for genetic reasons, so maybe. (Side note: this article includes the statistic that ~10% of the British population cannot smell Freesia.)

My suspicion that it's more that uninformed people are spouting off about subjects they're not personally acquainted with has something to do with the kinds of places where I saw the claim that they're stinky. The places claiming an odor tend to be talking about stapeliads or Huernias in general, or are general-info sites that appear to have gotten most of their information from other general-info sites. The people claiming first-person knowledge ("I am growing this plant, and it has flowered for me") tend to be the ones claiming no smell. This doesn't, in and of itself, prove anything (genetic smellers could be much rarer than non-smellers), of course.

Peter said...

These flowers are usually a lot more striped than yours. Interesting!

Individual variation can account for this, as well as for the variation in smelliness. Individual variation in the smellee (the flower) and in the smeller (you).

mr_subjunctive said...


The color has deepened slightly since the photos were taken, though not by a lot.


The stripes are less obvious in the photos on this post because of the angle at which the petals (petals?) are being held. As the flower's opened up more, the stripiness is much more evident.

Paul (not the other one) said...

I'd vote for reason #3 as well. I have never noticed a smell from mine and the person I originally got my plant from grew this particular species because it had no detectable fragrance unlike so many others.

As far as "They also seem to die shortly after they flower unless they're in a large clump", I'm unsure if he is refering to the plant or the flowers. If the plant is dying after blooming, then there is a problem with culture. I have bloomed H.z.'s about 1/2 to 2/3 the size of yours and the plant was just fine afterwards. If he's refering to the flowers themselves, IME, flowers of the Stap family do tend to be rather short-lived.

Pat said...

If you look up Huernia zebrina on this amazing website under "SI Database" (I don't think you can link directly but you might want to spend a little time there anyway) you will see three subspecies and 59 specimens with a lot of variation in stripiness, spottiness, shape, hue and colour of flower.

The PAN database allows you to check the validity of names within the Asclepiadaceae, as was, section of Apocynaceae as it is.

Wow, for once I am on the majority side of a division in Britain. I am usually an outlier but not for smelling Freesias.

Bom said...

Or the people actually growing the plant have developed immunity to the smell of the flower? It only takes an hour to adapt and it maybe very gradual from bud to bloom.

Then again, my nose has never adapted to durian no matter how long I am exposed to it.

mr_subjunctive said...


Even when you've adapted to a smell, though, if the concentration of the smell increases (like if you get closer to the source, or add more to the air), you notice it again, briefly. I couldn't smell the Stapelia gigantea at all when it bloomed, until I got right up next to it, and then it was perfectly obvious.

Jenny S said...

This is a little off-topic, but a few months back I bought a nice Huernia (it was unidentified but I'm pretty sure it's a zebrina). It's been slowly withering and dying. Soon after I got it I realized it was completely taken over with mealybugs, to the point where it was cottony. I was trying to read online about how to treat them, and everything I've tried hasn't worked.

Have you had any experience with this? It's still hanging on, just barely, and I'd love to save it.

mr_subjunctive said...

Sea Star Studios:

Well, I only just got mine, so I don't have any specific experience with mealybugs and Huernias.

Mealybugs in general, though . . . sometimes it's easier and cheaper to throw the plant out and buy a new one than it is to eliminate the mealybugs (especially if you have a lot of other plants). My personal best results have come from painstakingly cleaning the surface of the plant with Q-tips and rubbing alcohol every 3-4 days, plus moving the plant outside to a spot out of direct sun, plus adding imidacloprid granules to the soil. (The imidacloprid may not be available in your area, and some studies have suggested that it may be involved in killing honeybees, so you may not want to do that, but the first two are still good ideas.)

If a small piece of the plant looks like it may be salvageable, you can try taking it off and trying to root it on its own: it might prove to be easier to clean up a small piece of plant than it is to clean up a whole plant.

Anonymous said...

I just bought a bunch of Huernia, Stapelia, and Duvalia seeds. I was hoping they'd all be intensely smelly when they flowered in a few years, but you've dashed my hopes. Although, I almost like the form of the not-quite-fully-opened flower better than the fully opened ones. There seems to be more physical complexity, even though the colours may be a bit less vibrant.

Jenny S said...

Thanks for your reply. I think I will try to just salvage parts of it. I hope I can since I bought it at a succulent show a couple months back, and have never, ever seen one around here anywhere. It was beautiful when I first bought it and then just started withering away.

Hopefully I can save at least some of it.