Cold hardiness & minimum temperature

Is Golden Rat Tail Cactus (Cleistocactus winteri)cold hardy? Hardiness zone & min temp

Also called Rat Tail Cactus, Winter's Cleistocactus, Golden Cleistocactus.

More about golden rat tail cactus

About Golden Rat Tail Cactus

Cleistocactus winteri · also called Rat Tail Cactus, Winter's Cleistocactus · flowering

A sprawling to pendant Bolivian cactus with long, golden-spined stems producing vivid orange-pink tubular flowers along their length in spring and summer. Excellent for hanging baskets or cascading over shelves. It is easy to grow in full sun or bright indirect light with well-drained compost and moderate watering during the growing season.

Cold limit: USDA 9-11 · RHS H3 (7-35°C)

Watch for — Failure to flower: Most commonly caused by insufficient light or a missed cool, dry winter dormancy. Reduce watering and temperature slightly in winter to trigger spring flowering.

What golden rat tail cactus's hardiness rating actually means

Golden Rat Tail 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 9-11 — 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. Golden Rat Tail Cactus shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for golden rat tail 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 golden rat tail cactus go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 golden rat tail 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 golden rat tail cactus

Golden Rat Tail 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.

Golden Rat Tail Cactus hardiness — frequently asked questions

Is golden rat tail cactus cold hardy?

Golden Rat Tail 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 9-11 (and sheltered UK gardens) golden rat tail 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 golden rat tail cactus can survive?

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

What hardiness zone is golden rat tail cactus?

Golden Rat Tail Cactus is rated USDA 9-11 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can golden rat tail cactus survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 golden rat tail 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.