|University of Wisconsin-Madison | Plant Growth Facilities |
Botany Greenhouse
Carnivorous Plants
Carnivorous or insectivorous plants have evolved special adaptations, through modification of their leaves, to attract, capture and digest insects. Few are known to trap lizards, rodents, and small birds. These adaptations allow them to obtain nutrients, especially nitrogen, by secreting enzymes which break down and dissolve trapped organisms. These traps evolved into various forms, including the trumpet-shaped tubes of Pitcher plants (Nepenthes and Sarracenia), the foldings of the glandular tentacles of Sundew (Drosera), the triggered closing of the Venus's Fly Trap (Dionaea), the sucking action of Bladderwort (Utricularia) and sticky leaves of Butterwort (Piguicula).
Modification of Pitcher-type traps have evolved independently in these different, unrelated families of flowering plant: the Cephalotaceae (Albany pitcher plant) the Nepenthaceae (tropical pitcher plants) and the Sarraceniaceae (American pitcher plants)
Most of the carnivorous plants are herbaceous perennials adapted to sunny, boggy, sheltered locations with high humidity where the PH is very acidic and decay of organic matter is slow, thus the available nitrogen is in short supply. In cultivation, carnivorous plants require specialized conditions. The soil should be acidic and low in nutrients. Here at the UW-Madison greenhouses, we grow most species in a mix of: four parts sphagnum peat moss, one part silica sand and some horticultural charcoal. They are kept in humid conditions with wet medium by rain or deionized water to prevent mineral accumulation in the soil.
Brocchinia reducta - {Bromeliaceae}
Dionaea muscipula - Venus Fly Trap {Droseraceae}
Drosera spp. - Sundew {Droseraceae}
Nepenthes spp. - Nepenthes {Nepenthaceae}
Pinguicula spp. - Butterwort {Lentibulariaceae}
Sarracenia spp. - Pitcher Plant {Sarraceniaceae}
Utricularia vulgaris - {Lentibulariaceae}
