The Venus Fly Trap is a carnivorous plant which traps its prey, mainly consisting of arachnids and insects, using a structure made from the end section of each of its wide leaves, triggered by minuscule hairs found on its innermost surfaces. When one of these animals or insects comes into contact with a hair, enough to bend it, this mechanism will close if another hair is touched within 20 seconds of the first touch. This protects against wasting energy by trapping things which are not nutritionally valuable. Anything that isn't food while be rejected when the plant re-opens.
It's still not known entirely how the trap closes, in the absence of tendons, muscles or a nervous system, making these plants very mysterious - surely part of their appeal!
Venus Fly Traps are perennials, and collectors' items these days because of their rarity, and they are mostly grown in greenhouses. The good news is that they are one of the most straightforward plants of their kind to cultivate. They also make wonderful gifts!
Caring for a Venus Fly Trap
Venus Fly Traps actually need very few conditions to do well. But they do need a lot of humidity, lots of sunlight, moist roots and acidic, poor quality earth with good drainage.
A Venus Fly Trap is likely to arrive in rhizome or bulb form. It needs to be planted with the root side facing downwards so that the bulb's top is level with the dirt. Don't add lime or fertiliser, but use a soil mixture which has sand and sphagnum moss. For the Fly Trap to really thrive, ideally it will be replanted into new soil every few years.
Getting Light and Humidity Right
Planting a Venus Fly Trap in a glass container or terrarium with a small opening will maximise humidity - options include using an old fishbowl or aquarium. Be careful in the warmer months, since the glass can become very hot - don't place in direct sunlight. Two hours in the sun daily may be all these plants need - if they are wilting, they may need to be brought into shade sooner.
For plants being grown under artificial light, keep a good 10cm away from fluorescent lights.
In cooler weather, Fly Traps may need to be brought away from the window or covered at night-time so they stay moist and warm enough. During the cooler months these carnivorous plants also have a dormant period when they need lower temperature and less daylight. During these times, make sure the temperature is between 2 and 10⁰C. Increase light and warmth with the lengthening days.
Venus Fly Traps also do well in pots in bigger containers, like buckets, partially covered with Plexiglass or real glass so the air still circulates.
Long spindly leaves and a lack of a pink interior may mean more sunlight is needed.
The soil should be moist and the environment generally damp, but Venus Fly Traps shouldn't be allowed to stand in water constantly - so their pots need drainage holes. Gravel below the soil is a good idea for a Venus Fly Trap terrarium. Rainwater or distilled water is usually better than alkaline tap water.
If the plant is kept outside, and the container fills with rainwater, it won't be harmed, and it will get enough insects itself - but insects need to be fed to indoor Venus Fly Traps. During the growing season when the weather is warmer, a couple of small slugs or flies every month is adequate.
Once a Venus Fly Trap plant has matured, flowers may be produced above the leaves - high enough so that pollinating insects do not become caught. Each flower has minuscule seeds, which should be planted immediately or kept in the fridge. Pinching the flowers off will make the leaves grow more vigorously.
For plants with more than seven leaves it may be worth pulling one off and replanting. It will die off, and a new, much smaller plant will take its place.