Every October, carnivorous plants turn up next to the plastic skulls. A Venus flytrap is a perfect Halloween buy: it looks sinister and it moves. Then the traps go black, the plant shrinks, and it gets thrown out.
Most of those plants were not dying. They were going to sleep, and the warm windowsill they were moved to is what finishes them off. The fix is simple once you know which carnivores need a cold winter and which need the opposite.
01At a glance
- Need a cold rest: Venus flytrap, trumpet pitchers (Sarracenia) and temperate sundews.
- Stay warm all year: tropical pitcher plants (Nepenthes) and the Cape sundew.
- Cool but frost-free: the Albany pitcher (Cephalotus) and the sun pitcher (Heliamphora).
- All of them: rainwater only, no fertiliser, and no poking the traps.
02Which ones sleep, and which don't
- *Venus flytrap (Dionaea).* Needs a winter rest. NC State Extension says day length is the main signal, and recommends a rest of at least 10 weeks at about 2–10°C (35–50°F).
- *Trumpet pitchers (Sarracenia). Need a cold rest, and most are tough. The Carnivorous Plant Society says most species survive down to about -10°C. The RHS rates Sarracenia purpurea hardy to around -15°C, but S. leucophylla* only to about -5°C, so check the label.
- *Sundews (Drosera). It depends on the type. The Carnivorous Plant Society says temperate kinds die back to a winter resting bud, and can sit in an unheated greenhouse or cold frame. The Cape sundew (Drosera capensis*), the commonest one sold, is the RHS's pick as an easy houseplant. It does not need a cold rest, and the RHS rates it hardy only in mild parts of the UK, so keep it indoors.
- *Tropical pitchers (Nepenthes).* No dormancy, says the Carnivorous Plant Society, though growth slows in short days. Highland types want at least 10°C, lowland types at least 15°C. A cold porch will kill one.
- *Albany pitcher (Cephalotus).* A gentler rest. The Carnivorous Plant Society recommends a minimum of 5°C and slightly moist compost in winter.
- *Sun pitcher (Heliamphora).* The Carnivorous Plant Society says they survive 5°C, but advises a winter minimum of 10°C and high humidity all year.
03What dormancy looks like
A resting flytrap looks like a mistake. NC State Extension says gardeners often find the traps "turned black and shriveled up" in November. That is normal: the plant survives below ground in its rhizome.
Trumpet pitchers brown off in the same way. Our trumpet pitcher profile says leave the old growth on for now, as it protects the crown, and tidy it off in late winter. A temperate sundew may shrink to a tight bud.
Rot is different. The Carnivorous Plant Society warns that a flytrap or Sarracenia kept too wet in winter can rot at the rhizome. Keep the compost just damp, and if in doubt, leave the plant alone until spring.
04What to read next
This note is the triage. The care itself is in two fuller guides:
- For the sleepers: your Venus flytrap isn't dying, it's dormant covers how cold, where to put it, and how to water through the rest. Trumpet pitchers get the same treatment.
- For all of them, all year: rainwater, no compost, no feed covers the three things that kill most carnivorous plants.
How we checked this
Every care and safety claim on this page is verified against horticultural and veterinary sources.
Sources: RHS — Carnivorous plants growing guide · RHS — Venus fly trap · RHS — Drosera capensis · Carnivorous Plant Society — Dionaea caresheet · Carnivorous Plant Society — Sarracenia caresheet · Carnivorous Plant Society — Drosera caresheet · Carnivorous Plant Society — Nepenthes caresheet · Carnivorous Plant Society — Cephalotus caresheet · Carnivorous Plant Society — Heliamphora caresheet · NC State Extension — Venus flytrap dormancy
Checked 12 October 2026. Where the RHS and the Carnivorous Plant Society disagree, we say so; if you grow these plants and know better, tell us.