Cold hardiness & minimum temperature

Is Fishhook Barrel Cactus (Ferocactus wislizeni)cold hardy? Hardiness zone & min temp

Also called Arizona Barrel Cactus, Candy Barrel Cactus.

More about fishhook barrel cactus

About Fishhook Barrel Cactus

Ferocactus wislizeni · also called Arizona Barrel Cactus, Candy Barrel Cactus · flowering

The Fishhook Barrel Cactus is a large, slow-growing desert cactus of the US Southwest and Mexico, named for the stout hooked central spines guarding its ribbed barrel body. Mature plants ring their crown with orange, red, or yellow flowers in late summer, followed by yellow fruit. It demands intense sun, fast-draining grit, and very sparing water.

Cold limit: USDA 8-11; tolerates brief frost to around -9°C when bone-dry and established · RHS H3 (21-38°C in growth; 5-15°C winter rest)

Watch for — Root and basal rot: Overwatering, especially in cool weather, is the main cause of death. Use a sharply draining mineral mix and water only when bone-dry; keep dry in winter.

What fishhook barrel cactus's hardiness rating actually means

Fishhook Barrel Cactus 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; tolerates brief frost to around -9°C when bone-dry and established — 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. Fishhook Barrel Cactus shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for fishhook barrel cactus 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 fishhook barrel cactus go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11; tolerates brief frost to around -9°C when bone-dry and established 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 fishhook barrel cactus 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 fishhook barrel cactus

Fishhook Barrel Cactus 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.

Fishhook Barrel Cactus hardiness — frequently asked questions

Is fishhook barrel cactus cold hardy?

Fishhook Barrel Cactus 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; tolerates brief frost to around -9°C when bone-dry and established (and sheltered UK gardens) fishhook barrel cactus can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature fishhook barrel cactus can survive?

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

What hardiness zone is fishhook barrel cactus?

Fishhook Barrel Cactus is rated USDA 8-11; tolerates brief frost to around -9°C when bone-dry and established and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can fishhook barrel cactus survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11; tolerates brief frost to around -9°C when bone-dry and established 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 fishhook barrel cactus 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.