Friday, July 15, 2011

By request: Crassula ovata

The more I think about the Crassula ovata problem I mentioned on Wednesday, the more I'm thinking that even if it's possible to save the plant, I don't necessarily want to. It's not as though I don't have plenty of its offspring, and it's never been exceptionally beautiful or anything. I mean, I still want to know what's going on, so I can do something if it begins to happen again, but saving this particular plant is maybe not a high priority. Just so we're all clear.

(Though I suppose it may be necessary to save this plant, or at least try to, in order to know how to save plants with this problem.)

Anyway. Pat had asked for a photo of the whole plant, so here's a photo of the whole plant:

This may or may not tell you what you need to know. For one thing, I cut off several branches when I took the close-up pictures, because I figured it was better to cut off the worst-afflicted branches than to keep them on, so the effective size of the stems and leaves is bigger than this. But then there's the issue of the root ball being much smaller than it should be for the plant's (previous) size, because whatever happened to it did away with a lot of the roots.

I also wanted to try to clarify something about the watering: ordinarily I determine whether to water a plant by feeling its soil with a finger, and if it's an ambiguous situation then I lift the pot to try to determine how wet it is by weight. If it's still questionable, then I usually go ahead and water, because the cycle is such that I won't come around to give the plant another shot at water for two weeks. With the plant in question, most of this determination was thwarted: the original pot was plastic, and large enough that I knew the soil surface could be dry while the interior of the root ball could be wet, so I tended to try to err on the dry side. I also had a lot of aquatic soil mixed into the potting mix, to promote drainage, which means that the plant tended to be heavier than it would be with a more standard mix, so when I tried to gauge moisture by weight, I probably tended to think it was wetter than was actually the case. (Also soil mixes with a lot of aquatic soil tend to be more difficult to stick a finger into, so I might not have been able to judge the surface moisture very well either.) And if it was ever questionable, I tended not to water, on the grounds that waiting an extra couple weeks wouldn't hurt it that much. So I think I thought it was staying wet for a long time, but it may not have been.


Rcstampyd said...

I have both the pure green leafed form, and the white and green variegated form(just to name a few!). My variegated form looks to be having the same trouble as yours.

My green leaved variety, is 10 years old, and has a trunk the size a little thicker than a soda can. Maybe the variegated form does not grow as fast? I have had periods when my green variety, has lost leaves, and it has snapped out of it. Honestly right now, when I moved it outside this spring. I got some sunburned leaves, and had to cut back some growth that got to leggy. But there are new leaves sprouting even along the old trunk. I think every spring I get some sunburned leaves. I might of given it a little to much fertilizer and pinched it back, too much, for winter indoor growth.

That said, I have read that you are supposed to keep them on the dryer side with slim fertilizer. And people keep them root bound. I don't really do that. I grow my plants in Pro-Mix soiless mix. My green leaved variety has been in a 8 gallon pot for years. But for the first 4 years, I repotted it once a year, to keep up with the growth. But, I probably am not going to put it in a bigger pot for a while. I am planning on giving it fresh soil this fall.

When growth is slow, or the plant is in need of a boost. I get it on a regular schedule of Superthrive and 1/4 20-20-20. I water once every week or two, in the winter. And in the summer, the plants stay pretty wet. Because they receive so much sun, I try not to let them dry out too much.

My plants get a south/east window, in the winter. And full/all day sun, in the spring summer outside. Okay, this is getting long but, I wanted to let you know what I do. It seems important to have a good root system...I guess you could say that about all plants!HA! I am interested in seeing your result, so I could maybe help my variegated form, even if it is a little different. I love reading your blog. Lots of good info! -Camille

Pat said...

I was going to say bin it but it probably will come back and it will have a lot of errm... character. However, it isn't ancient and the youngsters will be getting big soon. Perhaps do a scientific experiment on the young ones in different composts and sizes of pot as they mature.

Potassium bicarbonate solution sprayed on the leaves will stop the mildew spreading. I have read that potassium phosphates may work as well.

I am intrigued that you think it might have been watered less than you thought but they should be happy with very little water. Did you water in winter?

mr_subjunctive said...


I did water in winter, though that may or may not be very meaningful, since we do work fairly hard to keep the house at about the same temperature year round. (The spot where this plant was runs about 66-68F/19-20C in winter and 72-76F/22-24C in summer. Spring and fall vary quite a bit, but the winter and summer temperatures are pretty steady.)

Nancy in Sun Lakes AZ said...

I wish you would keep it for now and try to save it, so we all learn something ... maybe!
I say nix the aquatic soil first of all. I would plant it in potting soil with at least 1/3 perlite or pumice. The size of pot used should be according to the size of roots left. I've grown them in plastic and clay and I don't think it really matters. If there are a lot of dead, rotted roots, I'd clip them back. If you have a shady spot outside for now, it would probably recover quicker, but inside in a morning sun spot is good too. It needs good air circulation though. I'd water it after repotting and then wait until it dries down an inch or so (you won't have any trouble checking if you are using the suggested soil mix). Pieces may continue to drop off of it before it comes around, but hopefully it will. It's not too much work, is it?

Sentient Meat said...

I would chuck it, too, except for its use as a model patient.

Anecdotally, I have had this root-shrinkage problem with Crassulaceae, too. And it's happened more in clay pots than plastic.

I know it's a common and universal prescription among cactus and succulent hobbyists to say, "water less!", but I have the sneaking, contrarian suspicion that in some cases, the root areas are actually drying out a little too much, causing them to die back. (Particularly in clay pots.) Then when the plant is watered, it works hard to grow new root hairs again. In this "failing to thrive" state, it's also an easier target for pathogens.

Also... I know some people love Turface or other calcined clay, but some growers have reported a stunting effect when attempting a side-by-side comparison... with some plants. At the very least, it's possible that one of the soil constituents just isn't a good fit for Crassula ovata, given the other conditions.

I don't mean to re-start any religious wars which sometimes break out on garden sites on the topic of soil ingredients -- these are just some thoughts, based on my growing too many Crassula spp, and reading way, way too many garden websites... and in person, visiting many cactus and succulent club meetings and nurseries.

One handicap to my advice is that here in Los Angeles Z10a (Sunset 21), Crassula ovata & friends grow very easily outdoors. The main problem for all Crassulaceae here is root mealybugs, which are endemic.

Pat said...

It isn't the cold but the short days which are significant, though cold and wet together will make them rot. The winter in South Africa is the dry season and many succulents expect it and are perfectly adapted to it.

Your C. ovata will never flower if you keep it wet over winter. At those temperatures I might give it a shorter dry season, from late November to early March, perhaps. Don't worry if the leaves look a little shrunken by the end. That gives you a few more minutes for the important things in life.

stefanogiovannini said...

I bet the problem lies in the soil. Not sure what an aquatic mix is but possibly is the opposite of this plant needs. I mix a lot of perlite/gravel/fine bark with some orchid mix. I am growing some of these from leaf cuttings. They seem not fussy at all. On the roof.

The soil in the photo looks too muddy to me.

mr_subjunctive said...

Sentient Meat:

I'm not sure about the C. ovata, but I suspect some of my problems with C. muscosa and C. rupestris might have been related to not watering often enough. In those cases, I'll never know, 'cause I don't intend to try them again, though.

I've mostly been happy with the aquatic soil, though there is a fine line between enough and too much. With too much, the clay pieces seem to pack themselves tightly, so I can't feel the soil to know when it's time to water. It's a bigger problem in clay pots than in plastic, because with plastic, I can just flex the pot and break up anything that's packed too tightly.

[shudders at your mention of root mealybugs]


Aquatic soil is small pieces of fired clay; it's basically just there to take up space without absorbing water, so the pot dries out faster.

The soil in the pot now is mostly semi-decomposed bark, peat, aquatic soil, and perlite, in the approximate proportions 55:30:4:1.

stefanogiovannini said...

I would just put outside where it could get some sun and breeze. Let nature take its course one way or another. If I have plants that are not doing much indoors often putting them a few months outdoor solves the problem. You can lose all teh old leaves and new healthier ones will grow.

Anonymous said...

While reading all of the comments on the two posts, I kept thinking that the soil you put in the pot might be too acidic and compact too quickly, or it has simply soured. This happens when I somehow get more rotting/rotted bark or a new peat mix, or if no air is getting into the mix. Kind of like the way orchid bark breaks down and gets "muddy" choking out the roots and preventing drainage.

When in doubt I do this with my plants: 1) Soak them in a mix of quite warm sudsy water using Palmolive, or Joy dishsoap, (not one of the fancy new concentrated detergents) mixed with a many drops of bleach. Just throw 'em in there and get a fresh clean pot. I use clay. Heavy rocks in the bottom helps. Mix your soil with sand and lime to sweaten it up, well ahead of time. Think cactus mix. Stay away from bark-based mixes, in nature they do not grow on a pine or a redwood forest floor. After its 15 minute or more swim, remove all the gunk and cut off dead root zone stuff and trim back yukky top parts, and groom to make more pleasing shape. Put into the clean pot, with fast draining soil, I lightly spray it and the plant with water at the sink. Set asside in direct sun or as bright as you can manage. I water mine a bit every two to three weeks, or longer. If branches and leaves shed from the plant, it is too wet, telling it to quickly drop body parts for quick sprouting in good times to spread the colony. If too dry they shrivel a bit. Once/twice a year I soak the whole pot in a pail to remove salts and make sure the whole thing gets wet.

When the soil sours for whatever reason there is nothing to do but start over. It might even be stinky. Almost lost my huge 50+ year old Xmas Cactus. Absolutely no roots left on it. The sour soil rotted them all away.

Your Stimulus Package (Seattle)