Cold hardiness & minimum temperature

Is Palinha's Rock Rose (Cistus palhinhae)cold hardy? Hardiness zone & min temp

Also called Palinha's rock rose, Sintra rock rose.

More about palinha's rock rose

About Palinha's Rock Rose

Cistus palhinhae · also called Palinha's rock rose, Sintra rock rose · flowering

Cistus palhinhae is an evergreen shrub endemic to the coastal dunes and scrubland of south-west Portugal, closely related to Cistus ladanifer (gum rock rose) and sometimes treated as Cistus ladanifer subsp. sulcatus. It bears large, showy white flowers with a prominent yellow boss of stamens, and the whole plant is covered in a sticky, fragrant resinous exudate (labdanum). The species is rare in the wild and considered of conservation concern; in cultivation it requires sharply drained, poor, acidic to neutral soil and a sheltered, sunny position since it is not fully hardy in cold, wet winters. Cistus is not listed by the ASPCA as explicitly non-toxic; treat as mildly toxic as a precaution.

Cold limit: USDA 9-10 · RHS H3 (-3 to 30°C)

Watch for — Cold, wet winters causing dieback: One of the less frost-hardy Cistus species; cold, wet conditions combined with temperatures below -3°C (27°F) can cause severe dieback or kill the plant. Plant in a sheltered spot, against a warm wall if possible, and ensure perfect drainage.

What palinha's rock rose's hardiness rating actually means

Palinha's 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 9-10 — 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. Palinha's Rock Rose shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for palinha's 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 palinha's rock rose go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-10 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 palinha's 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 palinha's rock rose

Palinha's 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.

Palinha's Rock Rose hardiness — frequently asked questions

Is palinha's rock rose cold hardy?

Palinha's 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 9-10 (and sheltered UK gardens) palinha's 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 palinha's rock rose can survive?

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

What hardiness zone is palinha's rock rose?

Palinha's Rock Rose is rated USDA 9-10 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can palinha's rock rose survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-10 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 palinha's 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.