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Dionaea muscipula
Dionaea muscipulaor, as it is popularly known, the venus flytrap (vft) is probably the best known carnivorous plant in cultivation, with millions being propagated in tissue culture and sold on the mass market every year. Unkown to most people, the native habitat of the venus flytrap is in a small area of North Carolina, where it inhabits boggy areas that can often become flooded in the spring, and relatively dry in the summer.
The traps of the vft are made up of two halves on the end of a petiole, and have been compared to clam shells in shape. Each half generally has three trigger hairs. To set the trap off, two of the hairs have to be brushed, or one hair twice in a row. The reason for this is to prevent falling rain, twigs, and so on, from falsely setting off the trap. But, this is getting ahead, first, it has to lure the insect. It does this presumably by nectar that it produces around and inside the trap, but as well as the red colouration inside the traps, which seems to attract insects.
When the trap is set off, it closes to the point where the cilia or 'teeth' intermesh with one another (think of it as putting your hands together wrist to wrist and closing them, intermeshing your fingers slightly). The gap allows in the cilia allow smaller insects to escape (as this would waste the plants energy digesting). If it is a larger insect, it keeps struggling, and the traps slowly compresses, secreting digestive juices, and consuming the nutrients of the insect. Up to two weeks later, the trap will re-open, revealing the husk of the insect. This can be repeated several times until the trap uses up all of it's resources, and dies (so no teasing the traps with fingers please!).
In it's native habitat, the vft competes with other grasses and sedges for available light. Traditionally, this habitat was burned on a regular basis through lightning strikes. One of the first plants to return from these burns was the venus flytrap, owing to the fact that they have underground stores in the form of a bulb-like rhizome. Fire swept through quickly, burning the leaves, but leaving this rhizome unharmed.
Today, the venus flytrap is protected from collection in North Carolina. Unfortunately, it suffers the woes of unscrupulous plant collectors, land developers, fire suppression, and farming. While it still does live in North Carolina, it's on the verge of being wiped out from its native area forever. Interestingly, the venus flytrap has been introduced into bogs outside of North Carolina and has successfully grown for many years in areas as far north as New Jersey, and as far west as California, Oregon, and British Columbia.
Species
There is only one species, Dionaea muscipulaalthough there are several different cultivated varieties (cultivars), such as 'Akai Ryu' (all red), 'Clamshell' (no cilia), and 'All green' (no red pigment inside the traps).
Soil and Containers
The best soil I have found is a 1:1 mix of peat moss (with no fertilizers, no chemicals added) and horticultural sand. This is very similar to the type of soil found in its native habitat. While some people grow vft's in sphagnum moss, I have always found this seems to slow growth, often due to the fact that the moss grows quickly and overwhelms the plant.
A good container is a six inch, full length plastic pot. Venus flytraps need a lot of room for their roots, and don't like them to be too wet. Place this pot in a 8 inch tray filled with water. You want the soil to be moist, not soggy.
Climate
Since Dionaea muscipulacomes from North Carolina, it likes to have warm (up to +30 degrees celsius) temperatures in the summer with a high humidity (up to 80%). In the winter, the plant is dormant, and this must be respected in cultivation. Keep the plant in a cool area (down to the freezing level), reduce watering and light period. The rosette of leaves will become very small at this time, or disappear completely. Don't worry, wait until spring and you should see new leaves starting to emerge. Think about other temperate plants you've seen, maple trees lose their leaves every fall, but return in the spring. The venus flytrap is following a similar cycle.
Propagation
The venus flytrap can be propagated from seed, leaf cuttings, division, and tissue culture. The easiest is division. When a plant becomes older, the rhizome becomes bigger and will eventually form clumps of plants (again, similar to the way tulip bulbs may propagate). These clumps can be taken apart in spring and potted up as separate plants. This can only be done every two or three years, to allow the plant to fully recuperate and begin forming new plantlets.
Leaf cuttings are also easy, but it takes up to two years to obtain a mature plant. I've found the easiest way to take cuttings is to pull down the long spring leaves until they peel off of the rhizome. You want to make sure to get part of the white base. These can then be put right side up into regular vft soil mix with the white base just underneath the soil layer. Within a couple of weeks, you may see new leaves emerging from the leaf giving you a new plant.
Seed is best sown in spring. Venus flytraps produce very long flower stalks (to prevent eating the pollinators and to get above the grasses) with small white flowers. While you can attempt to cross pollinate, the success rate varies, and the production of the flower stalk requires a lot of energy on the plants behalf. Better to remove the flower stalk as it forms, and purchase seed from a reputable dealer.
If you do successfully cross pollinate, the seed capsule will swell over the course of several months, eventually turning brown, splitting open, and revealing the shiny, black, pear shaped seeds. These can be sown, without burying them, on the standard mix and conditions. Germination may take up to a month with adult plants taking up to 5 years to grow from seed.
Tissue culture can also be used to propagate venus flytraps. Generally, sterilized tissue or seed is sown on agar and kept in highly controlled conditions (light, nutrients, humidity, temperature, etc.). Large numbers of venus flytraps are produced using this methods every year.
Seasonal Care
Since the soil is usually wet, breakdown occurs rapidly and plants will need to be repotted every two or three years. Dead leaves should be removed immediately to prevent fungus.
Pests and Diseases
The venus flytrap, and all carnivorous plants, is not without its foes. Think of it as revenge from the pest world! Venus flytraps are subject to infestations of aphids, mealy bugs, fungus, thrips, and other less annoying pests such as slugs, birds, squirrels, and racoons.
Of course, the best way to get rid of these pests is through prevention. Put the plants somewhere where they're out of reach of larger pests, or keep them in terrariums to prevent some of the smaller ones. Clip off all dead material to prevent fungus. Eventually though, you will encounter one of these beasties.
While it's best to try and remove all pests manually, or through a dunking in water overnight (don't worry, the plants can take it, they are flooded in nature every year), you may have to resort to more drastic measures. For pesticides, try to use a wettable powder form rather than pre-mix (which contains oils that can slow the plant down). I've used Diazanon with good success. Fungus can be treated with a fungicide such as Benomyl or Captan. Larger pests may require trapping out. Spreading wettable sulfur powder around the pots (not in the pots!) may help deter these urban critters. Some people have even used electric fences. Depends on how much value you put in your plants!