Cold hardiness & minimum temperature

Is Oak-leaf Primulina (Primulina dryas)cold hardy? Hardiness zone & min temp

Also called Oak-leaf Primulina, Oak-nymph-leaved Primulina.

More about oak-leaf primulina

About Oak-leaf Primulina

Primulina dryas · also called Oak-leaf Primulina, Oak-nymph-leaved Primulina · flowering

Primulina dryas is a striking gesneriad native to mossy cliffs and rocky outcrops in southern China, grown primarily for its dramatically silver-patterned, oak-shaped fuzzy leaves arranged in a flat rosette. In late summer to autumn it produces sprays of tubular lavender flowers above the foliage. It appreciates lower temperatures than many gesneriads and tolerates brief near-freezing conditions in its native habitat, making it slightly more cold-hardy than typical tropical houseplants. Primulina dryas is not individually listed on the ASPCA toxic plant database, so treat as mildly-toxic as a precaution.

Cold limit: USDA 10-12 (indoor in most climates) · RHS H1c (5–24°C)

Watch for — Leaf spotting from cold water: Fuzzy gesneriad leaves develop unsightly pale spots when cold water hits them; always use tepid water and apply it to the compost rather than the foliage.

What oak-leaf primulina's hardiness rating actually means

Oak-leaf Primulina is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10-12 (indoor in most 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 5 °C (and never frost). Oak-leaf Primulina has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for oak-leaf primulina as it gets too cold:

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can oak-leaf primulina go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 oak-leaf primulina can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Oak-leaf Primulina hardiness — frequently asked questions

Is oak-leaf primulina cold hardy?

Oak-leaf Primulina is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Oak-leaf Primulina can only live outside year-round in genuinely frost-free climates (roughly USDA 10-12 (indoor in most climates)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature oak-leaf primulina can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Oak-leaf Primulina has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is oak-leaf primulina?

Oak-leaf Primulina is rated USDA 10-12 (indoor in most climates) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can oak-leaf primulina survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to oak-leaf primulina below its minimum temperature?

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.