What in the world is as weird and wonderful as carnivorous plants? At first, it seems so odd and wrong that some plants can eat animals. Yet seems to me that bug eating is a remarkable and inspiring adaptation to the tough circumstances in which these species eke out a living.
The weirdness is what attracts most people to the Venus flytrap, a familiar childhood oddity, although it is an endangered species in the wild in the southeastern U.S. Most domesticated Venus flytraps die quickly, clogged with bits of hamburger and exhausted by too much snapping. In order to keep carnivorous plants alive long-term in a terrarium or conservatory, it’s necessary to understand their natural history.
Most of these plants evolved in bogs so acidic that nutrients are not available to their roots. So they found another way to get the chemical elements that are essential to their survival and growth: from the air, in the bodies of insects. Since they can’t actually reach up and grab bugs, they often depend on subtle enticements and deceptions.
For example, pitcher plants often are brightly colored or have sweet nectar around the rim to invite the gullible. An insect that lands for the sweet treat finds the footing so slippery that it falls into a vat of digestive juices, where it slowly dissolves.
Venus flytraps lay their leaves wide. When an unsuspecting insect lands to forage, it brushes against tiny hairs on the leaf surfaces. If the bug brushes against a couple of hairs in succession—indicating that it’s a moving insect, and not just a fallen leaf or seed—the leaves snap shut and digestion begins.
Sundews sit low to the ground, their leaves covered with sparkly, sticky goo. Any tiny bug that stumbles into the goo will be fatally glued.
Carnivorous plants are challenging to grow as houseplants. Because they evolved in such a narrow range of conditions, their requirements are exacting. They need high humidity; if you don’t have a greenhouse, you’ll need a terrarium. Potting mix must be acid and barren. Fertilizer is fatal. Distilled water is essential to avoid minerals that the plants can’t tolerate. As fun as it is to see a flytrap snap shut, it’s important not to overfeed them.
To learn more about carnivorous plants, I highly recommend starting with the highly amusing and informative website of scientist and author Barry Rice (sarracenia.com). You may find carnivorous plants at some specialized greenhouses and nurseries. Good starter species are Venus flytrap (Dionaea muscipula), cape sundew (Drosera capensis) and purple pitcher plant (Sarracenia purpurea).
Whatever you do, don’t collect these plants from the wild, and make sure you buy them from ethical dealers who never collect from the wild. Many of these species are or endangered species. It would be tragic to drive these weird and wonderful plants to extinction.