Cold hardiness & minimum temperature

Is Pink Storm Lily (Habranthus robustus)cold hardy? Hardiness zone & min temp

Also called Pink storm lily, Argentine rain lily, Pink fairy lily, Robust rain lily.

More about pink storm lily

About Pink Storm Lily

Habranthus robustus · also called Pink storm lily, Argentine rain lily · flowering

Habranthus robustus is a bulbous perennial native to Brazil and Argentina that produces large, soft-pink to rose-lilac funnel-shaped flowers on individual stems in summer and early autumn, reliably triggered by heavy rainfall after a dry spell. It thrives in full sun with good drainage and a summer-dry rest period that mimics its native wet-dry cycle. The single most important care fact is to provide a distinct dry dormancy in winter and avoid overwatering outside the growing season. All parts of the plant contain lycorine alkaloids and are toxic to cats and dogs.

Cold limit: USDA 7-11 · RHS H3 (10–30°C)

Watch for — Bulb rot in waterlogged soil: The most common failure; roots and bulb base become soft and malodorous when drainage is inadequate, especially over winter — always plant in sharply drained soil or pots with drainage holes.

What pink storm lily's hardiness rating actually means

Pink Storm Lily 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 7-11 — 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. Pink Storm Lily shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for pink storm lily 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 pink storm lily go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 7-11 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 pink storm lily 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 pink storm lily

Pink Storm Lily 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.

Pink Storm Lily hardiness — frequently asked questions

Is pink storm lily cold hardy?

Pink Storm Lily 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 7-11 (and sheltered UK gardens) pink storm lily can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature pink storm lily can survive?

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

What hardiness zone is pink storm lily?

Pink Storm Lily is rated USDA 7-11 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can pink storm lily survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 7-11 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 pink storm lily 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.