Cold hardiness & minimum temperature

Is Silver Pink Rock Rose (Cistus × argenteus 'Silver Pink')cold hardy? Hardiness zone & min temp

Also called Silver pink rock rose, Silver Pink cistus.

More about silver pink rock rose

About Silver Pink Rock Rose

Cistus × argenteus 'Silver Pink' · also called Silver pink rock rose, Silver Pink cistus · flowering

Cistus × argenteus 'Silver Pink' is a compact, mounded hybrid rock rose that arose as a chance seedling at Hillier Nurseries, Winchester, around 1910, believed to be a cross between Cistus creticus and Cistus laurifolius. It produces an exceptionally long season of delicate, pale silver-pink flowers up to 8 cm across, fading almost white at the centres, from late spring through late summer; the single most important care fact is that this cultivar needs full sun and sharply drained soil — wet winters are its main killer. It is one of the more moderately hardy Cistus cultivars, suitable for milder UK regions and sheltered city gardens. Cistus is not listed on the ASPCA toxic plant database; classified mildly-toxic here as a precaution.

Cold limit: USDA 8-10 · RHS H3 (-5 to 35°C)

Watch for — Crown and root rot in wet winters: Cold, wet soil over winter is the primary killer. Plant in fast-draining, gritty soil on a slight slope or raised planting, and cease all irrigation from early autumn. In marginal UK climates (RHS zone H3), grow against a south-facing wall for extra shelter and warmth.

What silver pink rock rose's hardiness rating actually means

Silver Pink Rock Rose 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 — 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. Silver Pink Rock Rose shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for silver pink rock rose 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 silver pink rock rose go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-10 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 silver pink rock rose 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 silver pink rock rose

Silver Pink Rock Rose 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.

Silver Pink Rock Rose hardiness — frequently asked questions

Is silver pink rock rose cold hardy?

Silver Pink Rock Rose 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 (and sheltered UK gardens) silver pink rock rose can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature silver pink rock rose can survive?

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

What hardiness zone is silver pink rock rose?

Silver Pink Rock Rose is rated USDA 8-10 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can silver pink rock rose survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-10 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 silver pink rock rose 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.