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What Are Carnivorous Plants?
This page gives a little bit of general background on carnivorous plants (cp's); where they grow, what they eat, and so forth. If you want detailed information on any particular genus or translation of the jargon used in this hobby, please refer to the cultivation page.
Definition: Carnivorous plants are plants which are capable of capturing prey and possess digestive glands for absorbing the breakdown products (generally nitrogen) of this prey. While there are some predatory fungi, the majority of plants grown are vascular and macroscopic (visible to the naked eye). This carnivorous nature has evolved over thousands of years, and is still evolving today.
Habitat: Carnivorous plants inhabit every continent on earth, with the exception of Antartica. In general, these plants grow in nutrient poor soils, most commonly in bogs, which necessitates their capturing of prey to sustain their growth, flowering, and reproduction. While a large proportion do inhabit boggy, peaty soils, there are some which grow in dry, arid regions, where rain fall strips the soil of most nutrients and organic matter, leaving behind sand. Due to their dependancy on capturing prey for growth, most cp's are smaller and slower growing than the common house and garden plants we are familiar with.
Traps:There are a wide variety of traps amongst the different species of carnivorous plants. They are generally broken down into activeand passivetraps.
Active traps are those which lure prey and then actively capture it. An example is the venus flytrap. When a fly land on the trap, it sets off the trigger hairs inside the trap, causing it to rapidly close. Active traps are also found in the Utricularia, Drosera, Aldrovanda,and Pinguiculagenera.
Passive traps are those which lure prey, but do not actively capture them. An example are the Sarraceniawhich produce nectar at the mouth of their pitchers. Insects feeding on this nectar move further into the mouth until they lose their footing and fall into digestive fluids below. Passive traps are also found in the Nepenthes, Byblis, Cephalotus, Heliamphora, Darlingtonia, Drosophyllum, Genlisea,and the carnivorous bromeliads.
Prey: In general, carnivorous plants consume mainly invertebrate prey (animals without backbones). However, they aren't picky and there are well documented cases of cp's consuming vertebrates such as frogs and rats. One grower I know who is also raises snakes feeds his large Nepenthestraps with deceased mice! He swears growth is much better with this 'unique' diet!
Numbers: There are over a dozen recognized genera of carnivorous plants and hundreds of species. It's very likely that there are cp's growing near where you live! The diversity of growth forms is incredible, not only amongst genera, but amongst species as well. Expeditions into the tropical rainforests, Australian outback, the highland tepuis of South America and even people's own backyard are revealing new species of carnivorous plants all the time.
Growing cp's: Carnivorous plants can be propagated by a number of methods, including seed, root cuttings, leaf cuttings, stem cuttings, division, rhizome/stolon cuttings, and tissue culture.
A large majority of the commonly grown cp's prefer a soil mix containing some peat and some sand. The peat lowers the pH to the proper level, is free of nutrients, and holds a lot of water, which these plants love! Water should be free of minerals, preferably rain water or distilled water, rarely tapwater. Fertilizers should not be applied, as this will generally cause root/leaf burn and death of the plant. While more experienced growers do use dilute fertilizers, this is not recommended for beginners and is not necessary. Most carnivorous plants prefer full sunlight, although there are some exceptions.
Some cp's have required dormancy period. This can either be a cool rest period or a dry one in response to seasonal changes and depending on where the plant originates from. If dormancy is not respected in cultivation, the plant will eventually weaken and die. This has been the cause of death for many venus flytraps!
Purchasing cp's: The only carnivorous plant you used to be able to commonly buy at nursery's was the venus flytrap. Nowadays, nurserys and even larger general stores are carrying a variety of plant including the venus flytrap, Droseraand even Nepenthes on occasion. Unfortunately, most of these plants do not come with adequate growing instructions and end up in the compost. Forunately, more nurseries dedicated to growing carnivorous plants as a large part of their business are becoming more common. A listing of some of these can be found at the links page.
In terms of cost, carnivorous plants are generally cheaper through specialty dealers. However, they do cost more than your average houseplant, due to the time it takes to raise them. Some cp's, such as the Nepenthescan cost over a hundred dollars! It's best to hold off on buying those ones until you have more experience with the cheaper, easier to grow species!