Cold hardiness & minimum temperature

Is Gryphon Begonia (Begonia 'Gryphon' (Begonia x hybrida))cold hardy? Hardiness zone & min temp

Also called Gryphon Begonia, Gryphon, Shrub Begonia 'Gryphon'.

More about gryphon begonia

About Gryphon Begonia

Begonia 'Gryphon' (Begonia x hybrida) · also called Gryphon Begonia, Gryphon · houseplant

Gryphon is a robust cane-type Begonia hybrid grown for its large, palmate, silver-and-green star-shaped leaves. Give it bright indirect light, well-draining soil that dries on top between waterings, and good airflow to prevent rot and mildew. It is toxic to cats, dogs, and horses per the ASPCA, so keep it out of reach.

Cold limit: USDA 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) (16–29°C)

What gryphon begonia's hardiness rating actually means

Gryphon Begonia 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 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) — 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. Gryphon Begonia shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for gryphon begonia 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 gryphon begonia go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) 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 gryphon begonia 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 gryphon begonia

Gryphon Begonia 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.

Gryphon Begonia hardiness — frequently asked questions

Is gryphon begonia cold hardy?

Gryphon Begonia 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 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) (and sheltered UK gardens) gryphon begonia can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature gryphon begonia can survive?

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

What hardiness zone is gryphon begonia?

Gryphon Begonia is rated USDA 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can gryphon begonia survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8–10 (grown outdoors as a perennial/annual; treated as a houseplant or container plant in cooler zones) 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 gryphon begonia 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.