Carnivorous Plant Cultivation Guide – Genlisea (aka Corkscrew Plant)
by Dave Sackett
Disclaimer: I have been growing genlisea since March 2003 and I have experience growing G. violacea, G. violacea ‘Giant’, G. margaretae, G. lobata, and G. hispidula.
Your best bet is communicating with people who grow genlisea and to experiment with different cultivation techniques to determine what works best for you and your particular plant. Here are some general guidelines that have worked for me:
Terrarium or windowsill
I would suggest starting to grow them in a terrarium where the growing conditions can be better controlled. I have done experiments with growing them on windowsills and I do better growing them in terrariums.
I have found that Long-fibered Sphagnum Moss (aka LFS) has given me the best results. I have also tried various combinations of peat and sand, which also work. A top dressing of sand is a nice contrast to make the plants look better, but I have found it harder to maintain. Undrained containers are fine, but I tend to submerge the plant every now and then, which the plant can tolerate. If there is a bottom drain, you can place a pot within a pot and keep the water level high to saturate the traps with water; a similar way that some people grow utricularia. I keep mine waterlogged and I don’t let them completely dry out.
I have tried moderate to fairly bright, but no direct sun. I keep most of mine on a constant 16 hour light cycle to simulate summer all the time. I typically use LED plant grow lights, but two 40-watt cool white florescent tubes about a foot away will work just as well. There are different opinions about how much light they can tolerate. The leaves will grow long and thin if the light is inadequate
I usually keep the humidity from moderate to 100% (terrarium is better).
Stale air and using pond water increases the likelihood of mold in a terrarium. I think a fan would be helpful or at least keep a gap for airflow into the terrarium.
The temperature should remain above 70 ° F; I think I have lost a few to temperature dips to the low 60’s. These are tropical plants (no dormancy required) and I have lost most through experimenting with lower temperatures.
I use pond water to feed/water them. When I don’t use pond water, I use rainwater. I have experimented with using tannin-enriched water from oak leaves falling into my rain collection bucket. I have a theory that it could help prevent mold and it makes the potting media more acidic.
Some claim that a light foliar fertilizer is beneficial, but the most I have used is watering with water from a pond that is high in nitrogen.
When the media breaks down or the plant outgrows its pot, it should be transplanted. There are no roots to worry about, but there are underground traps that are fragile. I have yet to transplant one with losing some of the traps.
They can be propagated by removing a complete leaf, including the white base, and planting it onto wet LFS. I usually cover the white base piece with some LFS. If the leaf disappears, it did not work. Also, the flower scape can be planted on LFS for new plants. Trap cutting work well with genlisea that are difficult to propagate from leaf cuttings.
Pitfalls to avoid
Creeping Moss: Certain mosses can crowd out genlisea plants. The vast majority of new leaves sprout from the middle of the same rosette, so they do not spread across the surface of a pot like some utricularia can. Occasionally, new leaves will sprout from the underground or surface traps. I use a top dressing of LFS to help prevent the spread of the smaller, invasive mosses.
Mold: I think good air circulation and a top dressing of LFS should help keep it at bay.
Slime Mold: They can be affected a slime mold. It is usually black/dark green and can overtake the plant’s leaves. I have taken cotton swabs to clean each leaf and that seemed to do the trick.
Die-back: After the plants blooms, there can be some “die-back” whereby some leaves die and other turn yellow/light brown. They have typically come back without changing any of the growing conditions. I have lost all of the leaves on some plants, and they eventually grew back from the traps.
Aphids/Other pests: You can submerge a genlisea plant in water for many days. Aphids breathe air and will drown or float to the surface. A few drops of cooking oil will help prevent aphids from reaching the air at the surface.
The Savage Garden pages 286 – 289 by Peter D’Amato ISBN 0898159156, Ten Speed Press