Cold hardiness & minimum temperature

Is King Henry Venus flytrap (Dionaea muscipula 'King Henry')cold hardy? Hardiness zone & min temp

Also called King Henry Venus flytrap, King Henry flytrap, Giant Venus flytrap.

More about king henry venus flytrap

About King Henry Venus flytrap

Dionaea muscipula 'King Henry' · also called King Henry Venus flytrap, King Henry flytrap · houseplant

Bred by Don Elkins of Mesa Exotics specifically for massive size, 'King Henry' ranks among the top three largest Venus flytrap cultivars in cultivation. Traps reach up to 4.5 cm, borne on long upright petioles. A fast grower that matures in just two seasons. Like all flytraps it demands full sun, pure water, and a cool winter dormancy. Pet-safe per ASPCA.

Cold limit: USDA 5–8 · RHS H3 (5–35°C (growing season 18–30°C; dormancy 2–10°C))

What king henry venus flytrap's hardiness rating actually means

King Henry Venus flytrap is half-hardy (RHS H3). 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 H3 means: Half-hardy — comes through mild UK winters outside but is killed by a hard freeze. On the US scale that maps to USDA 5–8 — 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 −5 to 1 °C — a light, short frost only. King Henry Venus flytrap shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for king henry venus flytrap as it gets too cold:

Down to roughly about −5 to 1 °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 king henry venus flytrap go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 5–8 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 king henry venus flytrap can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H3 figure above.

Frost protection for borderline king henry venus flytrap

King Henry Venus flytrap 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.

King Henry Venus flytrap hardiness — frequently asked questions

Is king henry venus flytrap cold hardy?

King Henry Venus flytrap is half-hardy (RHS H3). 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 5–8 (and sheltered UK gardens) king henry venus flytrap can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature king henry venus flytrap can survive?

Minimum survivable temperature is roughly about −5 to 1 °C — a light, short frost only. King Henry Venus flytrap shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is king henry venus flytrap?

King Henry Venus flytrap is rated USDA 5–8 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can king henry venus flytrap survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 5–8 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 king henry venus flytrap 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.