Cold hardiness & minimum temperature

Is Hooded-leaf Pelargonium (Pelargonium cucullatum)cold hardy? Hardiness zone & min temp

Also called Hooded-leaf Pelargonium, Tree Pelargonium, Wild Malva.

More about hooded-leaf pelargonium

About Hooded-leaf Pelargonium

Pelargonium cucullatum · also called Hooded-leaf Pelargonium, Tree Pelargonium · flowering

Pelargonium cucullatum is a large, woody-stemmed shrub from the coastal fynbos and strandveld of South Africa's Western Cape, notable for its cupped (hooded), aromatic leaves and showy pink to mauve flowers. It is an important parent species in the breeding of regal (Martha Washington) pelargonium hybrids. Grow in full sun with excellent drainage and very sparing water; excessive moisture rots the woody base. Toxic to cats, dogs, and horses.

Cold limit: USDA 9-11 (overwinter frost-free elsewhere) · RHS H2 (8–26°C)

Watch for — Blackleg stem rot: Blackening and collapse of the stem base caused by Pythium or Botrytis in waterlogged, cold compost. Use very free-draining mix, water sparingly especially in winter, and ensure frost-free conditions.

What hooded-leaf pelargonium's hardiness rating actually means

Hooded-leaf Pelargonium 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 (overwinter frost-free elsewhere) — 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. Hooded-leaf Pelargonium shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for hooded-leaf pelargonium 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 hooded-leaf pelargonium go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (overwinter frost-free elsewhere) 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 hooded-leaf pelargonium 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 hooded-leaf pelargonium

Hooded-leaf Pelargonium 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.

Hooded-leaf Pelargonium hardiness — frequently asked questions

Is hooded-leaf pelargonium cold hardy?

Hooded-leaf Pelargonium 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 (overwinter frost-free elsewhere) (and sheltered UK gardens) hooded-leaf pelargonium can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature hooded-leaf pelargonium can survive?

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

What hardiness zone is hooded-leaf pelargonium?

Hooded-leaf Pelargonium is rated USDA 9-11 (overwinter frost-free elsewhere) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can hooded-leaf pelargonium survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (overwinter frost-free elsewhere) 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 hooded-leaf pelargonium 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.