Cold hardiness & minimum temperature

Is Forrest's Ginger Lily (Hedychium forrestii)cold hardy? Hardiness zone & min temp

Also called Forrest's ginger lily, Forrest ginger lily, white ginger lily.

More about forrest's ginger lily

About Forrest's Ginger Lily

Hedychium forrestii · also called Forrest's ginger lily, Forrest ginger lily · tropical

Hedychium forrestii is a tall, statuesque rhizomatous perennial collected by the plant hunter George Forrest in Yunnan, China, where it grows in moist, sheltered ravines and forest edges at moderate elevations. It produces large, showy white flowers with prominent orange-red filaments in late summer, giving a dramatic two-toned appearance. Ample moisture throughout the growing season and protection of the rhizomes from hard frost are the twin essentials for success. Hedychium species are considered mildly toxic to pets.

Cold limit: USDA 8-11 · RHS H3 (5–30 °C (rhizomes frost-tender below 0 °C))

What forrest's ginger lily's hardiness rating actually means

Forrest's Ginger 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 8-11 — 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. Forrest's Ginger Lily shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for forrest's ginger 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 forrest's ginger lily go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 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 forrest's ginger 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 forrest's ginger lily

Forrest's Ginger 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.

Forrest's Ginger Lily hardiness — frequently asked questions

Is forrest's ginger lily cold hardy?

Forrest's Ginger 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 8-11 (and sheltered UK gardens) forrest's ginger 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 forrest's ginger lily can survive?

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

What hardiness zone is forrest's ginger lily?

Forrest's Ginger Lily is rated USDA 8-11 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can forrest's ginger lily survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 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 forrest's ginger 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.