Cold hardiness & minimum temperature

Is Orange River Lily (Crinum bulbispermum)cold hardy? Hardiness zone & min temp

Also called Berg Lily, Veld Lily, South African Crinum.

More about orange river lily

About Orange River Lily

Crinum bulbispermum · also called Berg Lily, Veld Lily · flowering

Orange River Lily is a hardy South African Crinum with strap-shaped greyish-green leaves and elegant pale pink to white funnel-shaped flowers in summer. Among the hardiest crinums, it tolerates brief frosts. Like all Crinum species, it contains Amaryllidaceae alkaloids and is toxic to dogs, cats, and horses.

Cold limit: USDA 7-10 · RHS H3 (5-30°C)

Watch for — Bulb rot in wet winters: The biggest risk for this species in cold, wet climates; lift bulbs before hard frosts or plant in very free-draining soil on a slight slope.

What orange river lily's hardiness rating actually means

Orange River 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 7-10 — 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 −5 to 1 °C — a light, short frost only. Orange River Lily shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for orange river 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 orange river 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 orange river 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 orange river lily

Orange River 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.

Orange River Lily hardiness — frequently asked questions

Is orange river lily cold hardy?

Orange River 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 7-10 (and sheltered UK gardens) orange river 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 orange river lily can survive?

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

What hardiness zone is orange river lily?

Orange River Lily is rated USDA 7-10 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can orange river 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 orange river 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.