Tag Archives: roridula gorgonias

December Ice Storms Bring January Surprises

Roridula gorgonias

If any real good came out of last month’s Icepocalypse and January’s rollercoaster weather, it came in the demonstration of seed germination difficulties. Several years back, I attempted to get results with seeds from the famed semi-carnivorous plant genus Roridula, both species dentata and gorgonias, and ran full-tilt into the challenges of Texas weather. Specifically, I finally got one batch to start sprouting around the end of summer, right when I was about ready to give up and toss the pots. They were doing beautifully until we had a panic about impending cold weather, and I brought them inside. That’s when I learned one of the big secrets to Roridula husbandry: they have no tolerance of stagnant air conditions as seedlings, and they all perished of fungus infections within two days.

This time, the issues were even worse. I replicated the conditions for the previous success, but the seeds simply refused to come up all year long. I figured “Well, it can’t hurt to leave them in their pot and see if they emerge in spring.” Do they? Nope: the little monsters are precocious. Instead, right after getting a second Arctic blast right after New Year’s Day, I came out to the greenhouse to assess any potential damage and discovered these little guys popping up all over the place. I can’t make any promises as to having Roridula available to the general public by summer, but it’s more encouraging than before.

Stylidium graminofolium

Roridula isn’t the only semi-carnivorous plant that seems to need fluctuating warmth and cold for best germination results. Having lost my last Stylidium graminofolium plants in the Heatwave of 2011, I missed that distinctive grasslike triggerplant, and started fresh with new seeds. Guess what decided to greet me last weekend? When lecturing on carnivorous plants, I regularly point out that many carnivores thrive on benign neglect. One of these days, I need to pay attention to my own advice.

Autumn serendipity

In the house, it may be spring cleaning, but the best time to clean out the greenhouse from stem to stern is in autumn. Well, it is in Texas, where we’re still seeing temperatures considered “balmy” in higher latitudes. It’s warm enough that I can clear out all of the tropical plants, check for spots that need to be clipped, and set them outside for a few hours , but it’s also cool enough that the usual pests are at a minimum. After this year’s horrible mosquito season, I enjoy any day where the smell of citronella tiki torch oil doesn’t get into my pores.

This sudden stripdown and rebuild was particularly important, as the greenhouse was underneath an aging and rapidly dying silverleaf maple, Silverleaf maples were a rather popular addition to many North Texas suburbs forty years ago, where they promised rapid growth and extensive shade. Well, both are true, but they also live about as long as our indigenous cottonwoods, and anybody in the area knows that you never want to encourage cottonwoods in your back yard. This silverleaf offered plenty of shade for the first two years we were here, but it was obvious that it was having problems after last year’s drought, where its companion planting didn’t make it. The tornadoes in April only compounded matters, and it’s now become a wreck. The tree’s heartwood is now nothing but punk wood and fungus, the dead branches produce a never-ending fall of sawdust from boring beetles, and the live ones threaten to fall if you look at them cross-eyed. I regret not being able to leave it alone, but either it comes down, or it takes the whole adjoining house with it, and possibly a neighbor’s house as well. Sic transit gloria.

In order for the tree to come down, the greenhouse had to come down and relocate, and that’s where the joy came in. Last summer, I learned exactly why nobody ever uses citrus wood when examining my Buddha’s Hand citron: one of the branches that died during the 2011 freeze had sprouted a single water shoot before it expired, and now the rather larger branch was hanging onto its roots by a sliver of tissue and a handful of dry rot. Pull out the rooting hormone, starter trays, and lots of rich potting mix, and start setting cuttings. Surprisingly, more cuttings survived than died, and if the state department of agriculture gives a full approval that these are disease-free, they might be up for sale within the state of Texas next year. Of course, that’s also dependent upon what sort of winter we have this year, so I’m not saying anything else.

No, the real surprise was getting ready to pitch a flat of presumably dead seeds and seeing a flash of green. Last spring, I purchased a set of seeds for Roridula gorgonias, a singular carnivorous plant from South Africa. Both species of Roridula look like gigantic sundews, but they can’t absorb nutrients directly from the insects and other animals they capture. Instead, in their native biomes, they depend upon a symbiotic relationship with an indigenous ambush bug, where the bug feeds on the prey, it defecates on the leaves, and the plant absorbs nitrogen and phosphorus from the feces via special channels in its leaves. I’d had suspicions that established plants would do very well in the Dallas area, but the problem was getting established plants. Repeated attempts with seeds, both in standard peat mixes for carnivores and in peat mixes exposed to smoke, did no good, and I was about ready to give up.

It turns out that I was just a bit premature. This latest batch hadn’t sprouted at all over the spring or summer, but it finally started germinating in November. The trick, apparently, is both to expose the seeds to high heat (daytime highs above 40 degrees C) and to let the soil mix dry out for a week. The seedlings, obviously, can’t handle complete dryness, but they apparently need much drier conditions than in a standard germination flat to get established. I’ll try some experiments this winter, but between this and the sudden cold front we had two weeks ago, something set off the little monsters.

In the meantime, I understand all too well why Chinese panda breeders refuse to name a baby panda until its eyes open, because the mortality rate among infant giant pandas is so high. Hence, no pictures until we get the first full set of true leaves. That may happen before we know it, but you won’t know if the seedlings suddenly succumb to fungus. If they take off, though…

New experiments, from South Africa to Texas

I use one particular phrase to describe my life these days: “I love living in the future.” I was already a correspondence junkie back then, but I’d have never guessed twenty years ago how many interesting folks I’d know from all over the world. Canada, Australia, England, New Zealand, Russia, Armenia, China…if someone offered me the chance to go back to 1991 and had the power to do so, I’d just smile and nod until the schlub turned his back, and then I’d beat him to death with a beanbag chair. (Now, if this opportunity were to stand on a hilltop some 150 million years back to watch the asteroid strike that produced the Tycho crater on the moon, I’d take him up on it. I may be crazy, but I’m not stupid.)

One of those interesting friends is Nerine Dorman from South Africa. Although best known throughout the world for her fiction, she and her husband are South African flora enthusiasts, and she forgets more about South African Euphorbia species in her sleep than I’d learn in a month of Sundays. One of these days, if money and time allow for significant travel, I want to stop by and say hello, and follow her and her husband for the next few days as they showed off local flora. I probably wouldn’t say a word the entire time, except to ask questions while taking frantic notes.

Many other friends describe my enthusiasm for sharing information with such words as “enabler” and and “pusher” and “damn you for making me empty my bank account.” In Nerine’s case, I can say the same thing about her. She introduced me to Silverhill Seeds in Cape Town, which in turn introduced me to what may become my nemesis or my salvation. That plant is Roridula gorgonias.

Both species in the Roridula genus are native to South Africa, thriving in remarkably similar conditions to those of Texas. Superficially, they resemble sticky-leaved carnivorous plants such as sundews and rainbow plants, but they don’t secrete mucilage such as these or dewy pines. Instead, the tips of their leaf threads produce resin. Mucilage allows the transfer of nutrients and digestive enzymes, but resin can’t, so naturalists thought for a century that any insects caught by Roridula were only incidental captures. Technically, since it also didn’t produce any digestive enzymes, Roridula doesn’t technically qualify as a carnivore, as it can’t digest and absorb any nutrients from captured prey.

The reality revealed itself relatively recently. Both species of Roridula have channels in their leaves, and both have unique species of assassin bug that live among the foliage. In the wild, the assassin bugs converge on captured prey in the Roridula leaves, having the ability to pass through the threads without sticking to the resin. They drain the prey, and then later defecate on the leaves. Those channels mentioned earlier trap the feces and allow the plant to absorb the nitrogen and phosphorus within, thereby making it a carnivore by proxy. That is, depending upon the expert you consult, and the discussion of Roridula‘s carnivory is quite the active subject within carnivorous plant circles.

Well, it’s time for the Triffid Ranch to jump into the fray. A fresh batch of seeds of R. gorgonias went into the greenhouse for germination, and since Roridula apparently loves the two things Texas summers have in abundance, heat and sun, I’m keeping close tabs on if and when they germinate. In three years or so, well, R. gorgonias should make a spectacular addition to lectures on odd plants, when these seedlings are full-sized. And until I can get to Cape Town and thank Nerine personally, I’ll have to settle for photos if this little experiment works out.