Cold hardiness & minimum temperature

Is Mountain Soursop (Annona montana)cold hardy? Hardiness zone & min temp

Also called Mountain Soursop, Wild Soursop.

More about mountain soursop

About Mountain Soursop

Annona montana · also called Mountain Soursop, Wild Soursop · tropical

An evergreen tropical tree closely related to soursop (Annona muricata) but more cold-tolerant and faster-growing, native to the Caribbean and Central America. Produces large, spiny green fruits with aromatic white flesh. Suitable for warm subtropical climates in USDA zones 9b–11. Performs best in full sun with consistent moisture and well-drained soil.

Cold limit: USDA 9b–11 · RHS H1b (15–35°C)

What mountain soursop's hardiness rating actually means

Mountain Soursop 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 9b–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 10 °C (sustained cold below this is damaging). Mountain Soursop has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for mountain soursop as it gets too cold:

Below about about 10 °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 mountain soursop go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °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 mountain soursop can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Mountain Soursop hardiness — frequently asked questions

Is mountain soursop cold hardy?

Mountain Soursop 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. Mountain Soursop can only live outside year-round in genuinely frost-free climates (roughly USDA 9b–11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature mountain soursop can survive?

What hardiness zone is mountain soursop?

Mountain Soursop is rated USDA 9b–11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can mountain soursop survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °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 mountain soursop below its minimum temperature?

Below about about 10 °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.