Purple pitcher plant care guide

A hardy bog plant that needs a cold winter

The purple pitcher plant, also called the northern or common pitcher plant, grows wild in bogs and wet, acidic peat from Canada to the southeastern United States. Its squat, curved pitchers sit in a rosette close to the ground and are open to the sky, so they fill with rainwater. Insects that fall in drown and are digested. Nodding, deep purple-red flowers rise above the pitchers in late spring.

It is a hardy perennial, not a tropical plant. It needs full sun in summer and cold temperatures in winter for its dormancy, which is why it rarely does well as a year-round houseplant. It is a different plant from the tropical pitcher plant, Nepenthes, which must stay warm, and it is often grown alongside the Venus flytrap and the Cape sundew as one of the easier carnivorous plants. Never plant it in ordinary potting compost, which is too rich. Use a carnivorous plant mix such as peat or sphagnum moss with sand or perlite. Large clumps can be divided every few years.

Dormancy is easy to recognize. In autumn growth stops and many pitchers turn brown and die back. That is normal. Cut off only the brown, dead parts, because green pitchers still feed the plant and can last up to two years. Flowers come first in spring, followed by a new set of pitchers.

From spring to autumn, stand the pot in a tray of rainwater a few centimeters deep and never let it dry out. Use only rainwater, distilled or reverse-osmosis water, never tap water, because the plant is sensitive to the minerals and chemicals in tap water. Check the tray often in hot weather, since small pots dry out fast.

In winter, while it is dormant, keep the compost damp but not waterlogged. Water from below, then pour away the excess rather than leaving the pot standing in water. The RHS advises keeping it slightly drier, cool and well ventilated in winter, but the compost must still never dry out completely.

Give it full sun, at least six hours of direct sun a day, ideally outdoors. In part shade the pitchers droop and do not color up properly. Behind glass, give it full light with some shelter from the hottest sun so the pitchers do not scorch. An indoor windowsill rarely gives a full-sun plant enough light without a plant light.

Do not fertilize it, and never put fertilizer in the compost, which can kill it. Do not feed it insects or food either. Let it catch its own prey outdoors.

It needs cold for dormancy, but first check the exact plant. The northern form, Sarracenia purpurea subsp. purpurea, and southern forms such as subsp. venosa differ in hardiness. NC State and Missouri Botanical Garden list the southern form for milder winter zones. RHS rates the species to around -15 °C (5 °F), but a pot’s root ball is more exposed to frost than roots in a protected in-ground bog. If a severe or prolonged freeze may fall below your plant’s limit, give the pot substantial root-zone protection or use cold, bright protected storage. A warm room starts growth too early.

It needs no special humidity. Outdoor air suits it, and wet compost and a water tray give it the moisture it needs. Good air flow matters more, especially in winter, when old leaves in a closed, stuffy spot can harbor pests and invite mold.