Carnivorous plants for house and greenhouse
Most carnivorous plants will thrive in a bright position inside, but not in direct sun leaves can scorch through glass. Tropical species such as Nepenthes, however, prefer a shadier spot as they would grow in jungle conditions in their native habitat.
Nepenthes (monkey cups)
These are plants from the tropics, their natural range extending from Madagascar through tropical Asia to northern Australia. In the wild they grow as vines up to 15m (50ft). Their insect traps are pitchers formed at the ends of leaves mainly in summer and high humidity is essential for pitcher formation. Two types of pitcher are produced, one at ground level, the other further up the vine. Pitcher development is encouraged by pinching out new shoots at four to six leaves or by cutting back annually in spring to maintain bushiness.
Grow in hanging baskets of rot-resistant wood, using a loose porous richly organic medium, such as a mixture of rough fibrous peat, a little fibrous loam, sharp sand, sphagnum-type moss (if available), or bark fibre, and some charcoal.
Lowland species require very warm summer conditions with a winter temperature of 21°C (70°F). Highland species need frost-free winter conditions with a winter night temperature of not less than 11°C (52°F), but prefer a good level of warmth by day ideally 18-22°C (64-71°F). Both groups need shade and high humidity.
Propagation: The best method is by stem cuttings (in February) or by seeds sown in a finer version of the growing medium at 26-32°C (80–90°F). Shoots near the base of the plant root most readily.
See the Nepenthes Grow Guide for more specific growing requirements.
Cephalotus follicularis (Australian pitcher plant)
Cephalotus is the only member of the genus. It produces squat pitchers 6.5cm (2½in) high. Pitchers are pale green in normal light conditions and purple in bright sunshine. The traps appear in summer and plain, fleshy leaves form in spring. Flower spikes up to 60cm (2ft) in height are produced, although they are not spectacular.
It is a plant for warm greenhouse cultivation. Grow in equal parts by volume peat, washed sharp sand and perlite (or vermiculite). Position in direct light (if attempting indoors, on a south or west-facing windowsill) maintaining a winter night temperature not below 10°C (50°F).
Propagation: The best method of propagation is by root cuttings (during April/May), leaf cuttings or division.
Dionaea muscipula (Venus' fly trap)
Venus' fly trap is the only member of the genus. It is a greenhouse plant, native to eastern North America, with green leaves that bear traps at the ends at all times of the year except winter. The inner surface of the trap may be flushed pink or red if healthy. Each trap can be used two or three times for catching insects, before it dies naturally and is replaced. White, insignificant flowers are produced in spring.
Grow in frost-free greenhouse or windowsill in direct sunlight. Grow in two parts by volume peat to one of washed sharp sand. Alternatively, use two parts oak- or beechmould to one part washed sand. Always water by filling the saucer with rain water.
In winter, the plant will turn dormant and requires much less water. Temperatures of not lower than 10°C (50°F) are preferred but a greenhouse or frame temperatures maintained above freezing point (0°C/32°F) is acceptable.
Propagation: Venus’ fly trap can be propagated by seed. Sow thinly on the surface of moist, shredded sphagnum moss or perlite. Moisten the surface then stand the pan in a shallow tray or saucer of rainwater. Cover with glass or clear plastic – cling film is ideal – then place in warmth, ideally in the region of 21-26°C (70–80°F), ventilating regularly. Seedlings take several years to mature.
By leaf cuttings take these in early spring or early summer, using the entire leaf and leaf base, but having first removed the trap. Lay the cuttings flat on the surface of moist, finely chopped living sphagnum moss. Ensure the upper surface of the leaf stalk is facing upwards before covering with a fine layer of moss. Good humidity levels are needed and the use of a small propagator is advisable, ideally providing bottom heat of 21–24°C (70–75°F). Several young plants may develop. They can be left for 12 months or more before being potted up singly.
Dionaea can also be divided, but this is best delayed until the plant has made four or more crowns.
See the Dionaea Grow Guide for more specific growing requirements.
Drosera (sundew)
Sundews are a good choice to grow with other houseplants to protect them from small flies, making a very effective fly paper. They come from a number of areas of the world and each group has its range of species with specific requirements.
All sundews can be grown in a cold frost-free greenhouse but pygmies such as D. occidentalis prefer a winter minimum night temperature of not below 10°C (50°F).
Compost must be kept moist during the winter for all protected species. Some need a period of dormancy with dry conditions during the summer.
Propagation: Seed is the most successful method of propagating sundews. Leaf cuttings are also effective.
See the Sundew Grow Guide for more specific growing requirements.
Pinguicula (butterwort)
A north-facing windowsill suits most species. During the growing season, ensure there is always 2.5cm rainwater or distilled water in the plants’ saucer. In winter keep plants moist, however the Mexican species and hybrids (P. x wesser, P. laueana need to be much drier than other species over winter as they can rot whilst not in active growth.
Propagation: Leaf cuttings are the most reliable method of propagation. Mature plants can be divided by hand.
See the Pinguicula Grow Guide for more specific growing requirements.
Sarracenia (American or trumpet pitcher)
Indoors, grow in bright light, but in direct sun. Stand the containers of equal parts by volume of moss peat and washed sand in a tray of rain or distilled water. Maintain a high level of humidity in summer.
In winter, sarracenias need to have a period of dormancy, so several weeks spent in temperatures of between 0°C (32°F) and 15°C (60°F) will help encourage strong growth the following year. Reduce watering winter, but do not allow the plants to dry out.
Propagation: Propagate by seeds or from rhizome cuttings.
See the Sarracenia Grow Guide for more specific growing requirements.