Cold hardiness & minimum temperature

Is Perez de la Rosa's Mammillaria (Mammillaria perezdelarosae)cold hardy? Hardiness zone & min temp

Also called Perez Mammillaria, Jalisco Pincushion.

More about perez de la rosa's mammillaria

About Perez de la Rosa's Mammillaria

Mammillaria perezdelarosae · also called Perez Mammillaria, Jalisco Pincushion · houseplant

Mammillaria perezdelarosae is a rare, compact pincushion cactus from Jalisco, Mexico, named in honour of botanist Juan Bravo Perez de la Rosa. It forms neat globose heads with distinctive spination and produces rings of small pink flowers in spring. A prized species among collectors due to its restricted natural range. Not toxic to pets.

Cold limit: USDA 10-11 · RHS H2 (10-30°C)

Watch for — Failure to flower: Requires a cool, dry winter rest of 8-10 weeks at around 10°C to set flower buds. Minimum watering during this period is key.

What perez de la rosa's mammillaria's hardiness rating actually means

Perez de la Rosa's Mammillaria 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 10-11 — 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 1 to 5 °C — tolerates cold but no real frost. Perez de la Rosa's Mammillaria shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for perez de la rosa's mammillaria 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 perez de la rosa's mammillaria go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-11 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 perez de la rosa's mammillaria 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 perez de la rosa's mammillaria

Perez de la Rosa's Mammillaria 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.

Perez de la Rosa's Mammillaria hardiness — frequently asked questions

Is perez de la rosa's mammillaria cold hardy?

Perez de la Rosa's Mammillaria 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 10-11 (and sheltered UK gardens) perez de la rosa's mammillaria can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature perez de la rosa's mammillaria can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Perez de la Rosa's Mammillaria shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is perez de la rosa's mammillaria?

Perez de la Rosa's Mammillaria is rated USDA 10-11 and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can perez de la rosa's mammillaria survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-11 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 perez de la rosa's mammillaria 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.