Cold hardiness & minimum temperature

Is Pink Rain Lily (Zephyranthes grandiflora)cold hardy? Hardiness zone & min temp

Also called Pink rain lily, Large-flowered rain lily, Zephyr lily, Rose rain lily.

More about pink rain lily

About Pink Rain Lily

Zephyranthes grandiflora · also called Pink rain lily, Large-flowered rain lily · flowering

Zephyranthes grandiflora is a free-flowering bulbous perennial from Mexico and Central America, producing large (up to 10 cm across), vibrant rose-pink, funnel-shaped flowers with a white throat and golden anthers from early to late summer, with blooms typically triggered to appear 3–5 days after rainfall. It is more tender than Z. candida and is best grown in containers in the UK, brought under cover from autumn through spring, while in warmer US climates (zones 7b–10) it can remain outdoors. Bulbs multiply rapidly into generous clumps that benefit from dividing every few years. Zephyranthes grandiflora contains Amaryllidaceae alkaloids and should be treated as mildly toxic to pets.

Cold limit: USDA 7-10 · RHS H2 (2°C to 35°C)

Watch for — Bulb rot in winter storage: Bulbs stored too damp during winter dormancy develop fungal rots; after lifting, cure bulbs by drying them in a warm, airy place for 2–3 weeks before storing in dry sand, coir, or paper bags at around 10°C.

What pink rain lily's hardiness rating actually means

Pink Rain Lily 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 7-10 — 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. Pink Rain Lily shrugs off cold nights but a real, sustained freeze will kill it.

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

It can live outside year-round only in the mildest, most sheltered part of USDA 7-10 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 rain lily 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 pink rain lily

Pink Rain 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 Rain Lily hardiness — frequently asked questions

Is pink rain lily cold hardy?

Pink Rain Lily 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 7-10 (and sheltered UK gardens) pink rain 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 rain lily can survive?

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

What hardiness zone is pink rain lily?

Pink Rain Lily is rated USDA 7-10 and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can pink rain lily survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 7-10 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 rain 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.