Monday, November 29, 2010

Zombie (Crassula rupestris and C. muscosa)


You know how sometimes you get a plant that never seems to do any more than just barely stay alive from one week to the next? I had a Crassula rupestris2 that was like that, from June 2007 until November 2009.

It's not that it didn't grow. It did. But branches also kept drying up. I'd snap them off and throw them away, and then a couple weeks later, there'd be more dead branches. The plant seemed to be able to produce enough new growth to break even, but still: it was annoying, and messy. Finally, one day in November 2009, something amazing happened: I tugged on one dead branch to snap it off, and the entire plant lifted up out of the soil cleanly, like a toothpick out of a cake. No roots at all. Checked the other plants in the same pot, and they didn't have roots either.

Crassula rupestris, before the long slow decline.

Now, I'd gotten it originally as unrooted cuttings, and hadn't messed with it much after sticking them in the pot, other than to water every couple weeks or so. It seemed to be okay with me not paying it a lot of attention. I mean, new leaves were forming. It was getting taller. So I thought we were fine, and it was just not a terribly impressive or interesting plant.

When I found out that these cuttings survived for two and a half years without ever even getting roots, it became much more impressive and interesting, in the way that you'd find your next-door neighbor more impressive and interesting if you discovered that s/he was missing all his/r internal organs or wanted to eat your brains or something. By which I mean that it kind of creeps me out. Plants are different enough from people that "undead" doesn't exactly apply here -- it can still be alive without roots -- but even so, alive without roots for more than two years is a pretty extreme situation, even by plant standards.

[no comment]

Upon making the discovery, I threw the plants away. My logic in the heat of the moment was that if they hadn't grown roots after two years, clearly they were never going to do so, and I needed the space for other, more appreciative, plants. The space part was true, but the rooting part probably wasn't. Maybe something could still have been worked out.

But I doubt it.

Crassula muscosa. This is the first one I tried.

This is sort of the way it goes with all my "stacked" Crassulas, like C. rupestris and C. muscosa.3 I really like the look of C. muscosa,4 and have bought it repeatedly, but basically the same thing happens with muscosa that happens with rupestris: a long, slow decline that eventually ends with the stems dying, one by one, from the soil level upwards. Sometimes it happens quickly, sometimes slowly, but inevitably, the plant dies. Some of this may be the fault of the sellers: I bought one muscosa that probably shouldn't have been sold until it was quite a bit better established, because it didn't have much for roots.

In any case, I'm probably not the person you want to be looking to for specific, helpful growing advice. Even when my plants survive for a long time, they're not in particularly good shape. Unfortunately, you don't have a lot of other options. I've googled. Lots and lots of sites, but most appear to have copied from the same original source or from one another, and the instructions are mainly for outdoor growing. This is the best I could come up with:

LIGHT: Outdoors, a lot of people say that direct sun all day long is too intense for C. muscosa, and it benefits from a bit of bright shade.

C. rupestris can handle more light outdoors. In very bright light, it will turn yellowish with red leaf edges, reverting to green if the light intensity diminishes.

Indoors, you probably want as much light as you can get, for either plant. When we lived in the apartment, I kept both in an unobstructed south window, and that appeared to be fine, though they both still stretched a little. You might want to consider growing your plants under bright artificial lights, if you don't have reliable sun or an unobstructed south window.5

My third C. muscosa (there are no pictures of the second), not long after I got it home.

WATER: Everybody contradicts one another on watering these plants. A few people even manage to contradict themselves in the same sentence (e.g. "Water sparingly or abundantly."). So I don't know. There does seem to be consensus that you should cut the water way back in the winter, if the plant's going to be at all cold (below 60F/16C). This doesn't explain my plants, though: I don't think any of them ever went below 60F. One of them actually fell apart in the summer, when I know it was never below 70F/21C.

I tried to water mine as I would for a jade plant (Crassula ovata): let it get almost completely dry, then drench; use a gritty, quick-draining soil; and water less in the winter. That doesn't appear to be quite right, but I don't know what I did wrong, exactly. Both species are from Southern Africa, so I suppose if you're in doubt, err on the dry side.

Really big C. muscosa in a garden center.

TEMPERATURE: C. muscosa is said to be able to survive temperatures down to freezing, but that only applies if they're dry. Plants that get chilled while in wet soil are likely to rot.

C. rupestris, in its native habitat, is supposed to be able to go even lower, to 25F/-4C, but I would assume that the same applies, that this is only doable if the plant is dry.

In neither case would I recommend that you actually let your plant freeze just to see how low it can go. If you're growing your plant indoors, then I hope finding out how close your plant can get to freezing without damage is hypothetical anyway.

HUMIDITY: Usually dry air is best, though see PROPAGATION below.

PESTS: I've personally had mealybugs on C. muscosa before; C. rupestris never had any bugs while in my care, but I would assume mealybugs would be the main problem there as well.

PROPAGATION: This may be where I went wrong with my C. rupestris cuttings: both species do best if propagated from pieces of stem that have been allowed to callus for a week (give or take), then stuck into coarse sand or some other very fast-draining mix, with good air circulation, bright light but no direct sun, and -- against all succulent-plant logic I'm familiar with -- misted a few times a day. Rooting is slow, and may take up to three months. Once the plant begins to produce new growth above ground, and doesn't pull out of the soil, you can move it to a spot with some sun.

I have successfully rooted C. muscosa before, both at home and at work, but I didn't have a particularly high success rate. I didn't do anything like the above instructions, though: I just cut (or pulled) a piece off and stuck it in dirt, which I watered occasionally. Better luck at work than at home, probably because of the higher humidity and bright, diffuse light in the greenhouse.

C. muscosa with flowers. They're unbelievably tiny.

GROOMING: I don't really have any grooming stuff for C. rupestris at all. Mine never actually did anything except lose branches.

C. muscosa has bloomed for me, which isn't exactly a grooming issue, but it deserves mention somewhere. I found the smell of the flowers somewhat unpleasant. This was actually PATSP's very first random plant event, and in that post, I initially described the smell as being like a private bathroom someone has just used, then sprayed a heavy, floral aerosol air-freshener around in. Later, I amended that to "a kind of musky, guy-put-on-cologne-six-hours-ago smell." I don't know whether the actual fragrance changes over time, or my perception of it changed as I got more accustomed to the smell. Either way, though. Strong, and borderline unpleasant. It only happened the once, though.

C. muscosa will also trail as it grows; the stems never get much taller than maybe four or five inches (10-13 cm). This is only worth noting because plants are usually sold as small, upright cuttings: if you expect your plant to maintain its upright habit, you're going to be disappointed very quickly.6 Pinching the tips might help induce more branching. I've never tried pinching personally, but Proven Winners suggests it, and pinching usually works with Crassulas.

C. muscosa #3, when I first got it. Notice how upright and branched and full it is. That didn't last long.

FEEDING: For both plants, feed lightly (half-strength or a quarter-strength) with every watering, except during the winter.

I've seen variegated versions of both plants. C. muscosa leaves are too small for the variegation to be particularly noticeable, and the plant just winds up looking like a lighter version of the species. Variegated C. rupestris, on the other hand, are kinda pretty, especially if they're getting red margins from being in bright light. (You have to get close to see it, but it's pretty.) There are a few varieties of C. rupestris with different-shaped or -sized leaves, as well, plus a decent number of hybrids with other Crassula species. Some of these can be seen at the link from footnote 3.

I don't like C. rupestris nearly well enough to try it again. I don't think I'd even asked for it in the first place. So no big loss there. I like C. muscosa quite a bit better, apparently, since I've tried it, on purpose, three times, but I don't think I like it four times' worth. There are too many possible good houseplants to keep failing with the same one over and over. At the same time, though, if somebody's got C. muscosa all figured out and wants to let me know what I'm missing, well, I'd be an attentive listener.


Photo credits: all my own.

References: (C. rupestris) (C. muscosa) (C. muscosa) (C. muscosa)
San Marcos Growers (C. muscosa) (C. muscosa) (C. rupestris)

1 I consider C. rupestris slightly easier (3.9) than C. muscosa (4.2), but it screws up the formatting if I try to put more than one difficulty ranking at the top of a post, plus the numbers are only very rough guides in the first place, so that's an average.
2 There's some uncertainty about whether this is C. rupestris, C. perforata, or something else. I sort of had to pick something for purposes of the post, and I found more photos of C. rupestris that matched my plant than I did of C. perforata, so that's what I decided it was. I wouldn't be heartbroken or anything if it turned out to be perforata, though.
3 Those two are the only ones I've tried, but there are a number of Crassulas with this general "stacks of leaves" look. Pictures of several such plants can be found at this post by Palmbob.
4 Sometimes C. lycopodioides; I've seen conflicting opinions about whether lycopodioides is its own, separate species or just an obsolete synonym for C. muscosa. says synonym; I actually can't understand what says but my guess is that they're saying synonym; and GRIN says synonym, so I think I'm on fairly solid ground to call C. lycopodioides and C. muscosa the same plant. In a retail context, you may see either name being used, though, so it's good to know both.
5 Sometimes this is necessary. I've had a few succulents that just weren't happy with me, even when I gave them a really good spot in a really good window, and didn't shape up until they were sitting a couple inches under a pair of shop lights. Sedum x rubrotinctum is one of those: I've had it forever, and it's always looked miserable in the window, but it's doing really well now under lights in the basement.
6 So of course one of the names the plant is being sold under is "princess pine," which to my mind implies an upright, conical plant with needles for leaves, not a trailing, snaky one with leaves so small they're barely visible. [shrug] I didn't name it that.
"Watch chain Crassula" is a much better name; the pattern of leaves does sort of resemble a small, thin chain.


CelticRose said...

Interesting. When I first bought my C. perforata and repotted it, I was surprised at how small the roots system was. When I repotted it recently, the root system was still on the small side.

About a week or two ago, one of the branches started producing aerial roots near the tip and the leaves were no longer succulent. It was obvious that for some reason water wasn't reaching that branch, so I cut it off. The rest of the branches are fine, and there's plenty of new growth.

Rameen said...

I have a succulent book that mentions misting your succulents to simulate morning condensation or something. It's vague with no distinctions, but it makes sense.

Some of my own plants to respond positively to regular misting, but only certain ones, and only at certain times of the day it seems.

Rameen said...

Also, in regards to your zombie plants: If they're growing and healthy, what more did you want from them?!

mr_subjunctive said...


Among other things, the C. muscosa stems tended to fall out of the pot when I was trying to water them. Also one suspects the C. rupestris would have grown better or faster or something if it had had roots to work with. I don't think I'm being entirely unreasonable here.

Pat said...

I think that when Tropicos give C. muscosa as the accepted name it means it is a synonym for C. lycopodioides but that it is the name that they think you should be using.

My nitrogen-overdosed C. volkensii is doing something odd at the growing tips, I hope the flowers are more pleasant than these.

Sentient Meat said...

I am the reverse. I like C rupestris more than C muscosa -- especially the large-leaf form of C rupestris I bought from Huntington Botanical Gardens. But I do really like C muscosa as a community plant, almost a garnish for other plants.

One of the things I like about home container growing is being able to grow little plants at the margins of bigger plants, and C muscosa is great for that.

By the way, I think the problem you outline here is fairly common in the genus Crassula (and in cultivation of many others in the family Crassulaceae, such as Echeveria). Sometimes the plants get so 'leggy' that the connection fails between the roots and the growing tip, or the plant may continue to grow fine but it starts to look awful. (Prime examples, C 'Ivory Tower' or Kalanchoe fedtschenkoi.)

That's a good time to cut the stem at or above the soil line, remove lower leaves (to make room for that section of stem to be planted), let all wounds callous, and plant the whole stem anew.

You'll get a more compact and balanced plant doing that every 2 to 4 years, or whenever the plant looks unbalanced or tippy. Plus sometimes the root system will sprout new growing heads, and you'll multiply your plants.

(Reviewing what I wrote, I'm convinced you already know all that, since it's similar to Synadenium grantii rubra, which we both know and love. But just in case, as a serious fan of Crassulaceae, I'll submit it anyway.)

mr_subjunctive said...

Sentient Meat:

I have some trouble with the callusing step, in that I'm often not patient enough to wait for it. The C. rupestris cuttings I got had gone through the mail, though, so they'd had plenty of time to callus. And that still didn't work. So I must have more problems than that.

Incidentally, you may be interested to know that the Echeveria coccinea looks like it's getting ready to flower. Or it's getting ready to do something weird, if not flower. I'll try to post about it soonish.

Megan said...

I've had most of these do okay inside with some decent afternoon sun. Check out this pic on flickr:
They're in clear containers, so I know they have roots :) They're slow growing inside. The ones outside are much happier. They're almost weed like (had to rub it in just a little).

Anonymous said...

"Princess pine" is a common name for Lycopodium sp., and if you've ever seen one you'd know why someone named Crassula muscosa "lycopodioides". The resemblance between C. muscosa and various members of Lycopodium is remarkable, though neither looks much like a pine tree, or for that matter much like a princess, either.


Anonymous said...

PS Have you tried using rooting hormone on C. muscosa?

Sentient Meat: I'd been thinking about using my C. muscosa to underplant a large succulent, in fact that's why I bought it, though have yet to break it up and do the experiment. Thanks for confirming that that's a reasonable thing to try.


Sentient Meat said...

Hi Mr S:

Not sure exactly the issue you had getting those Crassula spp to root. Sometimes that happens to me, too. These days I have pretty good luck with a VERY sharp-draining mix (1/4 or less cactus mix and at least 3/4 perlite and pumice).

Many Crassulaceae are 'winter growers', too, so you might try rooting them in the late summer or fall, right when they're waking up. They say that's the first growth stage for us fanciers of cactus and succulents -- learning which of our plants are summer or winter growers and how to treat them differently. (I have not graduated from that stage yet and I'm still haphazard in drawing the distinction.)

Often I'll root cuttings in a community pot, hoping the cuttings have a greater chance to colonize the medium before a fungus does the same. Rooting powder can help, though the wisest heads seem to agree the hormone part degrades quickly after opening... likely it's the still-active fungicide which gives young cuttings a chance.

For Crassulaceae, you might try letting them callus for 2 or 3 weeks and stripping a lot of the lower stem so you can plant a full 1/2 of its length. Additional leaf or stem calluses on the stripped stem are likely to be pluripotent and able to form new roots. If you want to get fancy, maybe add bright, diffuse light and bottom heat. Usually I just neglect the cuttings until they scream and cry and scold me into mixing up some medium and planting them in SOMETHING.

Cool about your echeveria! And yes, my Echeveria coccinea is about to do its thing, too. Same with some of my other echeverias, like my big 'Perle Von N├╝rnberg'. My 'Black Prince' opened its spike a few weeks ago but still seems to be flowering strong.

PS Oops, I used the wrong word for 'callus'. And me a writer! At least you were not callous in your silent correction.

Sentient Meat said...

PPS I meant strip the stem, THEN let it callus for 2 or 3 weeks. You want those leaf or stem separation points nice and healed over.

Pat said...

Fresh human urine is a reliable rooting hormone, it naturally contains large amounts of indolylacetic acid as long as you are eating protein. An old Romany tip, apparently.

I used to tell people this at my old job if they complained about the prices of the rooting hormones. Not within earshot of my bosses, obviously.

Unknown said...

I’ve been growing my C. mucosa outside in bright indirect light. It was placed unceremoniously on half a hollowed-out branch with a bit of shallow soil that I planned on planting more succulents in, until I realized that the branch was so shallow, the soil would partially wash away everytime I remembered to water it. After that, I forgot about it almost entirely... until one day, many months later, it caught my eye - the one plant that was left in it (C. mucosa) was huge! And suddenly very good looking, growing happily on the branch... WTF? Random... Now that it’s very much a plant I like and inappropriately take pride in, I have to do everything in my power to resist smothering it with love when it clearly prefers to be neglected on a dry dead branch. My guess is that it must be (at least) a semi-epiphytic succulent... Anyone have similar experiences with Crassula mucosa? Or is this case an anomaly?