Cold hardiness & minimum temperature

Is Button Cactus (Mammillaria prolifera)cold hardy? Hardiness zone & min temp

Also called Button Cactus, Strawberry Cactus, Cluster Pincushion.

More about button cactus

About Button Cactus

Mammillaria prolifera · also called Button Cactus, Strawberry Cactus · houseplant

Mammillaria prolifera is a fast-clustering pincushion cactus that forms tight mounds of small button-like heads fringed in soft white and yellowish bristly spines. After its cream-yellow spring flowers it sets small bright red, edible berries, earning the 'strawberry cactus' name. Vigorous and forgiving, it offsets freely and rewards a sunny sill with gritty soil and a dry winter.

Cold limit: USDA 9-11 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) · RHS H2 (10-30°C)

Watch for — Few or no flowers/fruit: Usually a missing cool, dry winter rest. Give it cooler temperatures and minimal water in winter to set its spring flowers and red berries.

What button cactus's hardiness rating actually means

Button Cactus is half-hardy (RHS H2). 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 H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) — 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 1 to 5 °C — tolerates cold but no real frost. Button Cactus shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for button cactus as it gets too cold:

Down to roughly about 1 to 5 °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 button cactus go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) 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 button cactus can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline button cactus

Button 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.

Button Cactus hardiness — frequently asked questions

Is button cactus cold hardy?

Button Cactus is half-hardy (RHS H2). 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 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) (and sheltered UK gardens) button 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 button cactus can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Button Cactus shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is button cactus?

Button Cactus is rated USDA 9-11 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can button cactus survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (often cited as tolerating brief light frost when dry, but best kept frost-free; grown indoors in cool climates) 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 button 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.