Cold hardiness & minimum temperature

Is Mountain African Daisy (Osteospermum jucundum)cold hardy? Hardiness zone & min temp

Also called Mountain African Daisy, Delightful African Daisy, Bergbietou.

More about mountain african daisy

About Mountain African Daisy

Osteospermum jucundum · also called Mountain African Daisy, Delightful African Daisy · flowering

Osteospermum jucundum is a rhizomatous herbaceous perennial native to the mountains of South Africa and Lesotho, producing solitary, light pinkish-purple daisy-like flowers 5–6 cm across with a contrasting dark eye from spring through autumn. It thrives in full sun with light, well-drained, moderately fertile soil and a warm, south-facing position. The key care point is to overwinter cuttings under glass in frost-prone regions, as the plant is only borderline hardy outside mild, coastal climates. Not confirmed toxic by ASPCA; exercise caution with pets.

Cold limit: USDA 9-11 · RHS H3 (-5–30°C)

What mountain african daisy's hardiness rating actually means

Mountain African Daisy 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 9-11 — 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 −5 to 1 °C — a light, short frost only. Mountain African Daisy shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for mountain african daisy 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 mountain african daisy go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 mountain african daisy 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 mountain african daisy

Mountain African Daisy 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.

Mountain African Daisy hardiness — frequently asked questions

Is mountain african daisy cold hardy?

Mountain African Daisy 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 9-11 (and sheltered UK gardens) mountain african daisy can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature mountain african daisy can survive?

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

What hardiness zone is mountain african daisy?

Mountain African Daisy is rated USDA 9-11 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can mountain african daisy survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 mountain african daisy 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.