Cold hardiness & minimum temperature

Is Short-Horned Sundew (Drosera brevicornis)cold hardy? Hardiness zone & min temp

Also called Short-horned sundew, Woolly sundew.

More about short-horned sundew

About Short-Horned Sundew

Drosera brevicornis · also called Short-horned sundew, Woolly sundew · tropical

Drosera brevicornis is a small tropical carnivorous perennial in section Lasiocephala, native to the Northern Territory and far north-west Queensland in Australia, where it grows on gravel slopes, creek banks, and shallow depressions in seasonally wet savanna. Unlike most sundews it has no dormancy period and demands consistently warm temperatures year-round — never let it drop below 20 °C. The petioles and leaf margins are covered in dense silky hairs that help trap moisture in the hot inter-monsoon period; keep humidity high and the soil permanently wet. Drosera is not listed in the ASPCA Toxic and Non-Toxic Plant database, but sundews contain plumbagin; classify as mildly-toxic until an authoritative listing confirms otherwise.

Cold limit: USDA 12 (indoor in most climates) · RHS H1a (20–35 °C)

What short-horned sundew's hardiness rating actually means

Short-Horned Sundew is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 12 (indoor in most climates) — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Short-Horned Sundew has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for short-horned sundew as it gets too cold:

Below about above about 15 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can short-horned sundew go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when short-horned sundew can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Short-Horned Sundew hardiness — frequently asked questions

Is short-horned sundew cold hardy?

Short-Horned Sundew is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Short-Horned Sundew can only live outside year-round in genuinely frost-free climates (roughly USDA 12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature short-horned sundew can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Short-Horned Sundew has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is short-horned sundew?

Short-Horned Sundew is rated USDA 12 (indoor in most climates) and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can short-horned sundew survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to short-horned sundew below its minimum temperature?

Below about above about 15 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.