Daily Archives: January 14, 2021

Winter Carnivore Cleanups – Frail Triggerplants

Backstory: it’s January, we don’t have any distractions, and the plants need us. Therefore, it’s time to discuss methods to clean up carnivorous plants for spring. For details, go back to the beginning.

Carnivorous plant enthusiasts tend to be a very sedate lot, and we’re usually incredibly mellow compared to rose or orchid growers and breeders. Oh, we might have personal preferences, but no raised voices or raised eyebrows or roundhouse kicks to the throat…with the possible exception of exactly how carnivorous a plant can be.

The official definition of “carnivorous plant” is “a plant with the ability to attract, capture, and digest insect or other animal prey.” Officially, a plant missing one of these three is designated protocarnivorous: plants that trap insects but depend upon animals to predigest that prey, such as the flycatcher bushes (Roridula) of South Africa, are protocarnivores, and this designation includes plants with insect-trapping hairs but that don’t actually absorb nutrients except after decomposition, such as tomatoes and potatoes. (There’s nothing like the look on a whole classroom of kids when I tell them that they’ve probably eaten two protocarnivorous plants in the last week, and then ask “So who here had fries with catsup?” In practice, this bounces all over the place: every other aspect of North American pitcher plants screams “carnivore!”, but they don’t actually produce their own digestive enzymes, and breakdown of trapped prey comes from bacterial action. Many plants listed as protocarnivorous later turn out to produce those enzymes under certain circumstances, such as with the carnivorous passionflower Passiflora foetida. And then we have the triggerplants.

The triggerplants of Australia (genus Stylidium) are a rather large group of endemic flowering plants, found mostly in the same environments that true carnivores such as sundews and terrestrial bladderworts. The common name comes from their unique blooms, but an additional thrill is that when blooming, the flower scapes are covered with multitudes of sticky hairs like those of sundews, but without the ability to move. Confirmation that they produce the enzyme protease only came through in 2005, and when the plants aren’t blooming, they’re about as carnivorous as a maple leaf. (Some people say “as carnivorous as a rosebush,” but anyone working with heirloom roses knows better: I regularly point out that the best documentary on working with heirloom roses came out in 2013 under the title “Pacific Rim.”) This sometimes confuses people unfamiliar with triggerplants, and they’ll repeatedly and understandably ask “So how is this (gesturing at a clump) carnivorous?”

The frail triggerplant, Stylidum debile, is probably the most common species in cultivation, for multiple reasons. Firstly, S. debile is a very enthusiastic grower, thriving under a very wide range of temperatures and weather conditions. They can freeze solid for a week and come back from their roots, and grow and bloom under heat that would kill most other carnivores. The blooms are also a major draw: unlike most triggerplant species, S. debile just keeps going all growing season, and in fact seem to need stress to encourage a bloom response. (To facilitate this, try to keep S. debile outside or at least in an unheated greenhouse, as too warm a winter cycle will discourage blooming in the next year.) The hot-pink blooms are only a couple of millimeters across, but what they lack in size they make up for in volume, with multiple blooms at any given time. Best of all, they stay small, meaning that they make excellent container carnivores, or protocarnivores, in containers far too small for a Sarracenia pitcher plant or even many sundews. The one thing they cannot tolerate, though, is an extended dry period: as with all true carnivores, triggerplants need to be kept moist at all times, and a plant that dies from lack of water won’t come back.

For this exercise, the following tools or their analogues are highly recommended:

  • Garden mat or old towel
  • Isopropyl alcohol, bottle or wipes
  • Hand cloth or paper towels
  • Spray bottle filled with rainwater or distilled water
  • Narrow garden shears or garden scissors
  • Long tweezers or alligator forceps
  • Tamper

This container was planted in 2020 from a plug about the size of a quarter, and as can be seen, new triggerplant shoots are filling the surface very nicely. In extreme cold, many or most of the leaves will frost and burn off, being replaced in spring, but the winter of 2020-21 so far has been nearly perfect for them, with low temperatures at or just below freezing. In this case, all that’s really needed is a bit of weeding (notice the grass stem coming up on the upper left, and clipping a few dying leaves. (Another really good thing about frail triggerplants is that dead leaves shrivel to almost nothing, meaning that dead leaf maintenance isn’t an ordeal or even a thing.)

As has been mentioned elsewhere in the series, Dallas weather can be incredibly variable through any given winter. We haven’t had any sleet, we had a tiny bit of snow that didn’t even stick, no severe windstorms, and no really abnormally warm days. Saying this now doesn’t mean that it won’t happen tomorrow, or at any time between now and the beginning of May. At this time, though, all this triggerplant needs is a thorough watering and a wipedown of its pot (more’s the pity that that I couldn’t get one of a preferable Green Lantern), and it’s good to go back to its growing space. In March, we should see new blooms coming up: if it’s safe to do so by then, they’ll make a great component of the next Manchester United Flower Show.

To be continued…