Cold hardiness & minimum temperature

Is Pygmy Sundew (Drosera scorpioides)cold hardy? Hardiness zone & min temp

Also called pygmy sundew, scorpion sundew.

More about pygmy sundew

About Pygmy Sundew

Drosera scorpioides · also called pygmy sundew, scorpion sundew · houseplant

Drosera scorpioides is a tiny Western Australian pygmy sundew forming a stalked rosette of dew-tipped tentacled leaves that glisten and catch small insects. It thrives in bright light, pure water, and lean acidic soil, and is famous for propagating from gemmae, tiny clonal buds it produces in cooler months. Compact and rewarding, it is pet-safe.

Cold limit: USDA 9-11 (a tender pygmy sundew, frost-sensitive) · RHS H2 (5-30°C)

What pygmy sundew's hardiness rating actually means

Pygmy Sundew is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 (a tender pygmy sundew, frost-sensitive) — 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 about 1 to 5 °C — tolerates cold but no real frost. Pygmy Sundew shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for pygmy sundew as it gets too cold:

Down to roughly about 1 to 5 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can pygmy sundew go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (a tender pygmy sundew, frost-sensitive) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 pygmy sundew can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline pygmy sundew

Pygmy Sundew is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Pygmy Sundew hardiness — frequently asked questions

Is pygmy sundew cold hardy?

Pygmy Sundew is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 9-11 (a tender pygmy sundew, frost-sensitive) (and sheltered UK gardens) pygmy sundew can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature pygmy sundew can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Pygmy Sundew shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is pygmy sundew?

Pygmy Sundew is rated USDA 9-11 (a tender pygmy sundew, frost-sensitive) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can pygmy sundew survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (a tender pygmy sundew, frost-sensitive) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect pygmy sundew from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.