Cold hardiness & minimum temperature

Is Alan Fradd Rock Rose (Cistus × purpureus 'Alan Fradd')cold hardy? Hardiness zone & min temp

Also called Alan Fradd rock rose, Purple-flowered rock rose 'Alan Fradd'.

More about alan fradd rock rose

About Alan Fradd Rock Rose

Cistus × purpureus 'Alan Fradd' · also called Alan Fradd rock rose, Purple-flowered rock rose 'Alan Fradd' · flowering

Cistus × purpureus 'Alan Fradd' is a distinctive hardy cultivar of the purple rock rose hybrid, bearing unusually large, tissue-thin white flowers with a bold crimson-maroon blotch at the base of each petal and a central boss of golden anthers, creating a dramatic bicolour effect from summer into early autumn. Despite the species epithet purpureus, 'Alan Fradd' is effectively a white-flowered form of this hybrid, which is itself a cross between Cistus creticus and Cistus ladanifer. Like all rock roses, the golden rule is full sun combined with sharply drained, lean soil — wet winters are far more lethal than frost. It tolerates coastal exposure and poor, stony soils with ease. Cistus is not listed on the ASPCA toxic plant database; classified mildly-toxic as a precaution.

Cold limit: USDA 7-10 · RHS H4 (-10 to 35°C)

Watch for — Root and crown rot from winter wet: The leading cause of plant loss, especially in heavy or clay-based soils. Plant in free-draining, gritty ground and avoid any mulch or organic material piled against the stem base. In marginal climates, grow against a warm south-facing wall for added thermal protection.

What alan fradd rock rose's hardiness rating actually means

Yes — alan fradd rock rose is genuinely cold hardy. Rated RHS H4 and USDA 7-10, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 7-10 — 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 −10 to −5 °C. Alan Fradd Rock Rose is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for alan fradd rock rose as it gets too cold:

It tolerates winter lows to about −10 to −5 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can alan fradd rock rose go outside or overwinter — and where?

Plant it out within USDA 7-10 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

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 alan fradd rock rose can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Frost protection for borderline alan fradd rock rose

Alan Fradd 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:

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes.
Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness.
Shelter new growth from late spring frosts with fleece if a hard night is forecast.

Alan Fradd Rock Rose hardiness — frequently asked questions

Is alan fradd rock rose cold hardy?

Yes — alan fradd rock rose is genuinely cold hardy. Rated RHS H4 and USDA 7-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Alan Fradd Rock Rose is hardy across USDA 7-10; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature alan fradd rock rose can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Alan Fradd Rock Rose is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is alan fradd rock rose?

Alan Fradd Rock Rose is rated USDA 7-10 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can alan fradd rock rose survive winter outside?

Plant it out within USDA 7-10 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

How do I protect alan fradd rock rose from frost?

At the cold edge of its range, mulch the root zone in late autumn to buffer the deepest freezes. Protect container specimens — pots freeze through far faster than open ground, costing roughly a zone of hardiness. Shelter new growth from late spring frosts with fleece if a hard night is forecast.