Daily Archives: January 11, 2021

Winter Carnivore Cleanups – Venus Flytraps

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.

By the middle of January, if you’ve decided to avoid the surefire ways to kill your Venus flytrap (Dionea muscipula), it should be dormant. Between the shortened days and cooler temperatures, if you haven’t forced it to stay active, it’s catching every photon it can get in its quest to turn sunlight and water into starch, in order to have enough energy on standby to get it through the next growing season. If outside temperatures went well below freezing, then most of the traps would be frosted off and blackened, but a core in the center of the plant will remain green. If it wasn’t exposed to that much cold, the long-stemmed traps it produced during spring are all or mostly dead, leaving a small cluster of short-stemmed traps close to the soil. Some of those traps may still close if triggered, so don’t trigger them: recent research suggests that a flytrap uses marginally more energy to reopen a trap than it would gain from that trap’s photosynthesis. Besides, it has few if any insects to catch this time of the year, and it wouldn’t have enough energy to produce the digestive enzymes it would need to consume them anyway. All we’re going to do here is clean them up a bit now, so as to avoid disrupting them when they’re coming out of dormancy in spring. (“Spring” in this context is defined by the date where generally the risk of late frost has passed. In the Dallas area, that date is usually around March 17, although we’ve had occasional later freezes all the way into the beginning of April. For the most part, though, the recommendation of flytrap dormancy stretching from “Thanksgiving to St. Patrick’s Day” holds, with the first new growth starting around then and the first blooms appearing by the middle to end of April.)

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

Everyone raising carnivorous plants has at least one story about Venus flytraps being thrown out by January because “I thought it was dead,” either by their hand or that of a loved one, and it’s a bit understandable. In the photo above, you can see three Venus flytrap cultivars: “King Henry” (left), standard flytrap (center), and “Aki Ryu” (bottom), and they’re way past their summer prime. The long-stemmed traps of summer and fall are all dead, and any latent color is now prominent. The Aki Ryu in particular looks dead, mostly because it blends in with the soil, but all three still have their central core alive and photosynthesizing. Leave them alone and keep them moist, and you should see the first new traps growing from the center, and maybe even new plantlets growing off the roots, by the vernal equinox. There’s no reason why we can’t clean up everything a little bit and make sure everything is okay right now, though.

The first thing to do is to remove any weed seeds before the plants get established in the spring. Grass seeds tend to turn up in sphagnum moss, and any plant exposed to the outdoors has a chance of seeds blowing in on the wind or transported by birds. Since the preferred soil mix for Venus flytraps is extremely acidic and nutrient-deprived, this tends to encourage the growth of opportunists such as clover and violets, and it’s much better to get them out now than later when they’ve choked out the flytraps half to death. When doing so, try to use forceps: they’re much more effective than fingertips at pulling out the entirety of a weed seedling instead of leaving the roots to come back later.

As with most carnivores, a good gauge for flytraps is “if it’s brown and dry, get rid of it.” Dead leaves aren’t going to revive, so snip them off with scissors and remove them. As tempting as it may be, do NOT try to yank or pull off dried leaves, as they tend to be stronger than the plant’s roots. Even if you don’t uproot your flytrap, you’ll still cause it damage which could lead to opportunistic infestations or infections, so take the effort to cut them off and remove the temptation.

And now for a bit of plant anatomy with this freshly trimmed model. Each leaf is separated into two lobes (the two sides of the trap) and the stem, officially known as a petiole. The petiole will perform some photosynthesis, but the overwhelming amount of photosynthesis is done with both lobes of the trap. On the edges of the trap can be seen the trapping hairs or cillia, and in the center of each lobe, in an equilateral triangle, are the sensory hairs that cause the trap to close.

(Fun fact: those sensory hairs are bioelectric generators, based on research published in 2020. Moving any hair generates a microelectric charge which dissipates after about 10 seconds, so either two hairs have to be tripped at once or any two hairs tripped within ten seconds to build up a charge that sets off specialized cells at the trap hinge and causes the trap to close. Well, the trap closes most of the way: prey that’s too small to be worth the effort are able to squeeze out and prey too large can just pull themselves out, and if the trap was accidentally set off by a passing animal or a torrential rain, the trap will reopen within a day or so. But if the prey hits the trap’s Goldilocks zone, though, that critter repeatedly brushing against the sensory hairs causes the trap to seal shut and release digestive enzymes, and the soon-liquefied prey is absorbed by the plant through glands all over the trap surface. Three to four days later, the trap opens up again, leaving the indigestible portions of the prey on the lobe surface to help attract spiders and ants in search of an easy meal.)

Thanks to the power of selective breeding, flytraps don’t just come in green. Several flytrap cultivars are all-red, with chlorophyll concealed with a red pigment. As you can see here, the red pigment is much like a suntan: give an “Aki Ryu” flytrap insufficient sun, and the whole plant will go the same green that appears here where dead leaves covered the live leaf surface. Because of this deep brick red coloration in dormancy, be especially careful not to cut off living leaves while attempting to remove dead ones.

Every once in a while, a flytrap will retain its long-stemmed traps into spring. Note the concave shape of the traps on the long stems: at this point, these traps are now nothing but photosynthetic surfaces, and almost always, no force on earth could get them to close, no matter how many times their sensory hairs are stimulated. So long as they stay alive, they keep transferring energy to the main plant. If it really bothers you, snip these leaves off as well, but this isn’t necessary.

(As a bonus, in the photo above, check out the spot on the trap on the bottom right. That used to be a young jumping spider, that was either attracted by an insect carcass in the trap or just happened to step in the wrong place while searching for prey. A surprising number of spiders get caught in flytraps, which suggests that the spiders are able to see into the ultraviolet spectrum far enough to see the UV-fluorescing patches on each trap lobe.)

Now time for a Before & After. In the “Before,” it would be understandable to assume that this flytrap was dead or at least dying. Only a couple of tiny traps are visible from underneath dead leaves, and the plant sure looks as if it’s about ready to kick it at any time. Let’s withhold judgment, though, until all of those dead leaves are out of the way.

What a difference a cleanup makes. This is the same plant without stems and leaves in the way, and without the violet seedlings that would have choked it out in spring. Technically, these are the same plants, as three plantlets to the right of the main plant are themselves getting established. Treat a flytrap right and give in the growing conditions it needs, and that one plant will clone itself over and over and ultimately fill this whole globe in a few years. If it becomes necessary to repot this flytrap, right now is a perfect time to do so, as it will be subject to a lot less stress when dormant than it would be if it were at the height of summer growing.

Finally, carnivores purchased from commercial greenhouses, or even carnivores grown in close proximity to others, have a tendency to pick up benevolent hitchhikers. Many sundews and bladderworts readily spread seed as far as they can during blooming season, and some of their progeny may show up in flytrap pots. In this case, we have two species: the sundews (probably Drosera spatulata or D. tokaensis) are pretty obvious, but barely visible are the tiny leaves from a terrestrial bladderwort, probably Utricularia subulata. Some carnivorous plant enthusiasts are adamantly opposed to these hitchhikers and will remove them at any opportunity, while others look at them as getting an additional carnivore for free. That’s completely up to you. Considering that these sundews won’t survive a cold winter, and that the bladderworts aren’t coming close to competing with the flytraps for room or prey, removing them is probably more trouble than it’s worth, and the brilliant canary yellow blooms of a good-sized U. subulata colony in spring are a welcome surprise.

To be continued…

Winter Carnivore Cleanups – “Novi”

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.

The enclosure is “Novi” (2018), and the plant therein is a Nepenthes burkei x hamata hybrid. Since both of its parents, N. burkei and N. hamata, are what are considered highland Nepenthes, it does best with cooler high temperatures (80 degrees F/27 degrees C) and even cooler night temperatures. In Dallas, this means that there’s simply no way to keep this plant outdoors in the summer, and a stout air conditioner to keep it cool is going to be a necessity here. (Being able to care for highland Nepenthes and Heliamphora, among others, is the biggest reason for starting the current gallery, as having a space isolated from outdoor temperatures between May and November is pretty much a necessity.) Crossing N. burkei, an exceptionally forgiving beginner plant, with N. hamata, one of the most notoriously prima donna carnivores known, leads to a child with hamata-like pitchers with wide serrated peristomes (which fluoresce brightly under ultraviolet light), but also with surprisingly pulpy and delicate leaves. Even more so than most Nepenthes, this hybrid seems to crave exceptionally high humidity, and getting upper traps growing may require a drip irrigator or an ultrasonic fogger to give it that level of humidity.

In this particular situation, two ferns planted in the back of the enclosure were in fern excluders, but the drop in temperatures and lower photoperiod in winter caused an explosion in new ferns, both from runners that escaped trimming and from new growth from spores. At the moment, they’re not interfering with the Nepenthes‘s growth, but it’s just a matter of time before they completely block off view of the plant from the front of the enclosure. The pitcher plant itself is starting to vine, but none of the new leaves are producing pitchers, and it has a new plantlet emerging from the roots. This cleanup is going to take a while, and it definitely needs a tub or other container to hold what gets pulled out.

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

  • Garden mat or old towel
  • Plastic dish tub
  • 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

In addition, the following may be necessary to attempt propagation of cuttings:

  • Rooting hormone or cloning gel
  • Shot glass
  • Propagation container (a large glass jar will work well)
  • Long-fiber sphagnum moss, soaked in rainwater or distilled water for at least 24 hours

First, let’s assess the condition of everything in the enclosure. The ferns have run amok, but they seem to have spread runners across the surface instead of digging deep, which makes cleanup a lot easier than expected. The Nepenthes has two pitchers from the main plant, one attempting to wedge itself between the glass enclosure wall and the backdrop and one freestanding pitcher, and one emerging from the plantlet at the base. There’s a lot of new growth in the ferns, but also a lot of detritus from older leaves dying off, and while the Nepenthes is attempting to vine and produce upper traps, those traps aren’t forming.

Firstly, the ferns need to go. To get a better look at the roots, cut back the majority of the leaves, and then gently pull the roots from the enclosure substrate. This may pick up chunks of sphagnum moss and even enclosure decorations, so go through slowly and carefully to prevent damage. In particular, make absolutely sure that you’re only cutting ferns at this stage: it’s far too easy to misjudge the placement of scissors and cut the rib connecting a pitcher plant pitcher to its leaf or cut the main stem itself.

When Nepenthes pitcher plants start to vine, the ribs on the end of each leaf will twine around anything they can touch to stabilize the new vine. In addition, new pitchers will wedge themselves between anything they touch and then fill with fluid, and they act as if they have a compulsion to inflate between an enclosure fixture and the glass enclosure wall. Removing a wedged pitcher usually damages the pitcher, and even an undamaged pitcher won’t straighten out and regrow. The pitcher above wedged between the enclosure wall, the backdrop, and a fern excluder, and that kink in the pitcher wall won’t straighten out for the life of the individual pitcher. If the shape doesn’t bother you, feel free to leave wedged pitchers alone, but damaged pitchers should be cut off at the rib and removed.

Since the Nepenthes is a bit leggy, it really needs to be trimmed back a bit. As to what to do with the cuttings, they can be pitched, or you can attempt to propagate them and get new plants for your trouble. For specifics on the best ways to propagate your Nepenthes, I highly recommend following Peter D’Amato’s methods in the book The Savage Garden (honestly, every carnivorous plant enthusiast who doesn’t have a copy of this book needs to buy it NOW), but in this case, I’m going for the tried-and-true method of cloning gel. I’ve had good results with Dyna-Grow Root-Gel and Olivia’s Cloning Gel, so after checking the stem for potential pests, it’s time to crack out the gel, a shot glass, and the sharpest scissors I have.

When attempting to propagate Nepenthes from cuttings, the first consideration is to minimize infection, so clean the hell out of your scissors or blade (some people use razor blades for the cleanest cut possible). After that, never never EVER dip your cuttings directly into the cloning gel container unless you’re only using it once: instead, put a dollop in a shot glass or other small container and dip cuttings into that. In my experience, I let each cut sit in the gel for at least 5 seconds and then pull it out, and then cut the leaves in half to cut down on water loss in the new cutting while it’s attempting to grow new roots. Depending upon the species or hybrid, you can plant the whole cutting, or you can cut between leaves and root each individual cutting.

Any number of factors can affect whether a cutting survives, but the absolutes for improving the odds are to give the cutting lots of humidity and lots of light. The one method that seems to give consistently good results (thus explaining why the gallery is overrun with Nepenthes bicalcarata and Nepenthes ampullaria clones) is to place the cuttings in a propagation dome (I use a 2-gallon glass jar) atop long-fiber sphagnum moss that has been soaked in rainwater or distilled water for at least 24 hours, and then get them under bright lights. In about a month, we’ll find out if these cuttings survive, mostly by seeing new leaves emerging from the top.

And back to the main enclosure. With the ferns cleared away, we have all sorts of options on what to do next. Want to trim back the live sphagnum to give a better view of new pitchers? Now’s the time to pull it back and shove the excess against the backdrop to stabilize it. Want to clean it out entirely and put in new top dressing? Go for it. The important part is that without the original cleanup, you can’t see options, and more might be done with this enclosure before winter is over. And depending upon what a new owner or renter wants, the enclosure may evolve even more over the years.

To be continued…