Venus Flytrap


Photo: Valery Beaud

National Agricultural Library
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Nepenthales
Family: Droseraceae
Genus: Dionaea
Species: muscipula
Binomial name
Dionaea muscipula
The Venus Flytrap is a carnivorous plant. It catches its prey (insects and arachnids, mostly flies and spiders) by snapping its leaves closed, much like animals do with their mouths; indeed, the edges of the leaves are equipped with protrusions that look like a set of teeth. Once the insect has been captured, the plant digests and absorbs it. The leaf then opens, and wind blows (or the rain washes) away the insect's remains. Each leaf can digest only several times, after which it withers and dies. The Venus flytrap may be the source of legends about man-eating plants.

The tip of the leaf is divided into two hinged lobes that form a trap. There are many traps on a plant, each on their own individual leaf. The trap is lined with tiny hairs (cilia) that act as the trigger for the trap. The inside of the trap has little red colored glands that attract insects. A hair must be touched twice in rapid succession (to prevent natural things like raindrops from triggering it), whereupon the lobes will expand and shut the trap. This action is very fast, typically well under a second. If the hairs are still being triggered, it will close tighter as well as release digestive enzymes that dissolve the insect. This normally takes about 10 days for one insect. However, if the trap closes and the hairs aren't being triggered, it will open after a few hours. It's very rare that a trap will catch even three insects in its lifetime.

The Venus flytrap is found in nutrient-poor bogs in the southeastern United States, mainly within a 100-mile radius of Wilmington, North Carolina. This is why it has to draw nutrients (especially nitrogen) from the insects that it can't find the soil. Collecting wild flytraps is severely restricted by federal and state law due to its limited range.

Keeping

Venus flytraps are popular as cultivated plants, especially in North Carolina itself. They can be grown on a windowsill if a few requirements are respected.

They thrive with at least a few hours of direct sunlight daily; they mustn't be roasted, however: hot sunlight combined with low humidity can spell death for a weak Venus flytrap fresh out of tissue culture. In other words, Venus flytraps thrive with as much light as possible without suffering overexposure therefrom.

Venus flytraps must not be watered with tap water; accumulated salts cause most carnivorous plants—including Venus flytraps—to slowly die. Gallon-sized jugs of distilled water (available at supermarkets) should be used instead. The soil should be kept moist constantly by placing the pot in a tray full of water. Ideally, growers should use a tray wide enough to let the water vapor created by evaporated tray water raise the plant's surrounding humidity.

Some horticulturists have experimented with giving small amounts of fertilizer to Venus flytraps, usually applying diluted solutions of products formulated for epiphytes, using cotton swabs, to the plant's foliage. Beginners (and those without expendable plants), however, would be wise to eschew fertilizer in favor of insects, below.

Growers should resist the temptation to trigger the traps manually, whether by poking them or by feeding them, say, hamburger, which shouldn't be used because of its tendency to rot traps. Venus flytraps are entirely capable of catching their own food; thus, feeding them oneself isn't necessary. Nevertheless, traps are best (manually) fed with live insects no larger than 1/3 of the size of the trap.

Also, growers should consider avoiding allowing their Venus flytraps to flower, since flowering consumes much of the plant's energy, reducing growth. Besides, the flowers have little aesthetic value.

Another important consideration is dormancy, an annual rest period undertaken by Venus flytraps. If one lives in an area with chilly, but not freezing, winters (similar to Venus flytraps' natural habitat in North Carolina), they can be placed outside in a cool area protected from frost. One must keep the soil slightly moist and ensure that the plant still receives a small amount of sunlight. Those who live in areas with extremely cold winters should place their Venus flytraps in a plastic "ziploc" bag in the refrigerator for two to three months, starting in autumn.

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