You know how there are certain plants you see everywhere? I'm talking about the plants that you know are going to be anywhere you go that sells plants, be it a garden center, a big box store, your local supermarket, the neighborhood florist's shop, or wherever. Now, I suppose that the precise list might vary a little, depending on where you are, but around here, it looks something like this:
Synadenium grantii1 is not one of those plants. In fact, it's not even easy to find if you're actively looking for it, at least not around here. What those five have in common is that 1) they're easily to produce, 2) they sell well, and 3) they can tolerate less than ideal care for a reasonably long time without falling to pieces. They're not necessarily the cheapest, or the prettiest, or the most durable: there's some tradeoff involved, but the eventual calculation is that every business has to carry them, so they all do.
There's also a longer list of plants which aren't everywhere, but they're still pretty common. Codiaeum variegatum is easy to produce, and easy to sell, though it kind of falls apart indoors in inexperienced hands. Plectranthus verticillatus is amazingly cheap, and can take a lot of abuse, but it's hard to get people interested in it. Zamioculcas zamiifolia is durable and a good seller, but requires a pretty big time investment to produce.
Synadenium grantii isn't on the longer list either, even though it seems like it would naturally fit in. It's a pretty durable plant, and it's extremely easy to produce – I've made two or three new plants from cuttings in a single year, and I wasn't even trying hard: I could have made more than that, if I had wanted. And it's not like my plant was old when I got it; it was just a six-inch cutting, barely even rooted.
I haven't been in a position to know whether it's a strong seller, because we've never offered it at work, and I've only seen it for sale anywhere two times in the last ten years, and in both cases I bought it myself on sight. I think we can all agree that I'm not a typical American tropical plant consumer, so the fact that I bought a couple doesn't necessarily mean anybody else would. But I would think so. They have a nice look to them. Fairly big, broad, yellowy-green leaves, with decorative specks of a contrasting color – easy to grow, easy to keep. So why are they not everywhere? Why are we not sick to death of seeing them?
It turns out that there are other considerations. Like, some plants get very big very quickly. My most recent Synadenium, which I bought last March, tripled its height by May and needed to be cut back. The plant then grew a bit more slowly before an abrupt halt in the winter, but it has put on about six inches in the last month and now needs to be cut back again. This is - don't get me wrong - awesome, but also a bit of a problem: most people don't want to buy a tabletop plant and have it turn into a ceiling-height tree in two years. (A few of us do want that, but we're in the minority.) Outdoors, a plant can supposedly grow 6 or 7 feet in a single growing season, at least in zone 9.
How big can they get? Hard to say. The tallest claim I found was 15-20 feet, but there's disagreement on the maximum height. (The University of Florida, for example, doesn't think they get above 8 feet. This is almost certainly wrong.) It's naturally found in east central Africa, and is apparently a regular tree there, though, so it will outgrow your home, if you let it, and it's not going to take that long to do so. Unless you have very high ceilings, or a machete. So that's one reason.
But there's a much bigger reason than that, which is: it's mean. Like its relatives the Euphorbias, which we've talked about some in the post for Euphorbia trigona, its sap is irritating, can cause temporary blindness and all that good stuff, except more so. We're talking redness, we're talking blisters, we're talking swelling and pain and possibly a little weeping and cursing. And it gets better still, because the reaction isn't necessarily immediate: you may not notice any problems until four or more hours after contact with the sap.
Also like with E. trigona, I've never experienced this problem personally, but then, I take precautions: I try to be near a sink or shower if I'm going to be cutting on the plant,2 I wash my hands and arms when I'm done, and if I see sap on myself before I finish, I stop what I'm doing and wash it off before I go on. This would, admittedly, be impractical if one is cutting a 15-foot tree outside: in that case you probably want to put on some actual covering: long sleeve shirt, long pants, closed-toed shoes, possibly a hat and goggles. This is, I know, a pain, but it's more convenient than temporary blindness and blistering, and you will, almost certainly, get dripped on, if it's a big enough tree.
Supposedly the sap is a Masai home remedy for East Coast fever, which illness sounds like somebody who just can't get enough crabcakes, but is actually a pretty unpleasant-sounding tick-borne disease which primarily affects cattle but can also kill (or at least seriously inconvenience) people. Synadenium grantii sap is said to be applied to the swollen lymph nodes, causing blisters on purpose. The protozoans who cause the disease eventually move into the lymph nodes, so I suppose if enough of the nasty compounds from the Synadenium sap cross the skin and get taken up by the lymph nodes, it sort of makes sense. Still pretty hardcore for a home remedy, or for any remedy.
Also relating to cattle, the same site as above reports that Synadenium grantii has been used in cow sabotage before, which, if you're city folk, stop and ponder the concept of "cow sabotage" for a second:
Thorold (1953) described the sudden development in 33 steers of large oedematous swellings between the brisket and near fore leg. Some also showed lesions between the hind limbs. No animal showed a lesion on the offside. Eight steers died. He believed that the lesions may have been caused maliciously using the latex of Synadenium grantii, a plant common in the nearby countryside.
Indoors, though, not such a big deal. Some paper towels, some soap, a sink nearby, goggles or glasses, and you should be more or less set.3 When propagating, use a clean knife to make the cuts, and let the cuts callus for a day or so before planting cuttings. I have found rooting cuttings to be kind of ridiculously easy: I just treat them like plants that have already rooted, and then suddenly they are already rooted.
But nevertheless. You can see how a plant that has the potential to blind people and sabotage their cows isn't likely to wind up in the grocery store, especially not if it might also grow a foot and a half while it waited to sell. That said, I am an unapologetic fan of this plant, and think more people should be growing it.
The plant comes in two color varieties that I'm aware of, the one I have, which is the appley-green with reddish spots, and the reverse of that, reddish-purple with green spots. I'm not sure if the red version is actually a cultivar, properly speaking, but people name it like one (variously as 'Rubrum,' 'Ruby,' rubrovariegata, or "var. rubrum"). The various names all do seem to refer to the same plant. I've seen the various "rub-" names being applied to the green plant with red spots, too, so make sure you see the plant (or a picture) before you buy, but the care for each is identical.
I used to have the reddish-purple variety, several years ago: I got what was probably a six-inch pot with three plants in it from Wal-Mart, and kept it for a while, but the stems got really tall really quickly, and I wasn't aware that I could cut it back, so when it outgrew the space I had for it, I threw it out. I am, of course, kicking myself for this now, but at the time, there weren't a lot of options. If and when I see another of the red-purple ones, I'll buy it.
Care is relatively simple:
Pests: I haven't had pest problems with mine, though I wouldn't be surprised at all if mealybugs and whiteflies couldn't cause problems, as both pests are common on Synadenium's relatives.
Temperature: Opinions vary on outdoor hardiness, but there seems to be general agreement that this plant is tough enough to take the occasional light freeze without long-term damage (they will drop most or all of their leaves after a light freeze, though, and there may be some damage to stems: it's not really something you want to encourage), so I would be surprised if temperature is ever an issue indoors.
Grooming: Not a huge issue. Plants will drop lots of leaves following a freeze, overwatering, or prolonged underwatering, but this isn't usually going to make such a mess that it's going to take you all day to clean it up. Pruning is useful if you want a plant to branch (supposedly they'll do this on their own, but I haven't seen it), or if you need to keep it underneath the ceiling, but where and how much is kind of up to you.
Feeding: As for any other houseplant.
Light: At least some sun; ideally a lot of sun. This is pretty much non-negotiable.
Water: Plants should get close to completely dry between waterings, especially in the winter. The plant reacts to too much water and not enough water in the same way (the lowest leaves yellow, crinkle up, and drop), so there's a bit of a learning curve at first, though once you've got the hang of it, it's no big deal.
Propagation: Described above.
Humidity: Not really an issue for this plant.
Supposedly, if you want a smaller plant, you can just keep it in a smaller container: if the roots are constricted, the plant will stay a more manageable size. So far, I haven't wanted a manageable plant, so I haven't tried this personally.
I have doubts that this is ever going to be a mainstay of the tropical foliage industry, and probably that's how it should be: it really is potentially a huge, dangerous monster. But, you know, an appealing, vigorous monster, too. Like tribbles. It certainly doesn't make sense that they should be so hard to find.
Photo credits: all me.
1 There are some on-line who say that this plant has been reclassified as a Euphorbia species, E. pseudograntii. This wasn't reported commonly enough that I necessarily believe it just yet, without some confirming evidence, but I wouldn't necessarily be surprised, either, as Synadenium grantii has a lot of Euphorbia-like qualities, and was already classed in the family Euphorbiaceae. Moving the relationship one step closer, and placing it in the Euphorbia genus, isn't really that big of a stretch. A few sources also identify this plant as Synadenium compactum, but it seems to be so well-known as grantii that I don't think I have to take compactum seriously.
2 Cold water seems to slow bleeding more quickly than just letting a cutting sit. Powdered charcoal is supposed to be even better, but it's a lot easier for me to get cold water than it is to get powdered charcoal.
3 (Also clothing. I don't advise taking cuttings of any plant while nude, but it's especially not a good idea with this one.)