Cold hardiness & minimum temperature

Is Star Apple (Chrysophyllum cainito)cold hardy? Hardiness zone & min temp

Also called Star apple, Caimito, Milk fruit.

More about star apple

About Star Apple

Chrysophyllum cainito · also called Star apple, Caimito · tropical

Star apple is a fast-growing tropical evergreen with strikingly bicoloured leaves, golden-bronze beneath and glossy green above. Its round purple or green fruit reveals a translucent star pattern when sliced, with sweet, milky pulp. It demands warmth, full sun and frost-free conditions, exuding sticky latex when cut. Grow under glass in temperate regions.

Cold limit: USDA 10-11 (greenhouse/indoor elsewhere) · RHS H1b (22-32°C)

Watch for — Cold and frost sensitivity: Very tender; foliage is damaged near 0°C and young trees can be killed by frost. Provide overhead protection or move containers into a frost-free space in winter.

What star apple's hardiness rating actually means

Star Apple 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 10-11 (greenhouse/indoor elsewhere) — 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). Star Apple has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for star apple 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 star apple 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 star apple can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Star Apple hardiness — frequently asked questions

Is star apple cold hardy?

Star Apple 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. Star Apple can only live outside year-round in genuinely frost-free climates (roughly USDA 10-11 (greenhouse/indoor elsewhere)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature star apple can survive?

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Star Apple has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is star apple?

Star Apple is rated USDA 10-11 (greenhouse/indoor elsewhere) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can star apple 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 star apple 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.