Cold hardiness & minimum temperature

Is Langsat (Lansium parasiticum)cold hardy? Hardiness zone & min temp

Also called Langsat, Duku, Longkong, Lanzones.

More about langsat

About Langsat

Lansium parasiticum · also called Langsat, Duku · tropical

Langsat is a beloved Southeast Asian fruit tree bearing clusters of round, translucent-fleshed fruits with a sweet-tart, lychee-like flavour. A shade-tolerant understorey tree in nature, it adapts well to humid tropical gardens and performs best in deep, fertile, well-drained soils. The 'Longkong' type has thicker skin that does not ooze latex, making it easier to eat.

Cold limit: USDA 10b–12 · RHS H1a (20–35°C)

Watch for — Fruit drop before maturity: Premature fruit drop is linked to water stress, nutrient deficiency (especially potassium and boron), or pest pressure during fruit set. Maintain consistent irrigation, apply foliar boron at fruit set, and monitor for fruit-boring insects. Mulching reduces soil temperature fluctuations that stress the root system.

What langsat's hardiness rating actually means

Langsat 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 H1a means: Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever. On the US scale that maps to USDA 10b–12 — 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 above about 15 °C (warm, never cold). Langsat has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for langsat as it gets too cold:

Below about above about 15 °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 langsat go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above above 15 °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 langsat can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1a figure above.

Langsat hardiness — frequently asked questions

Is langsat cold hardy?

Langsat 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. Langsat can only live outside year-round in genuinely frost-free climates (roughly USDA 10b–12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature langsat can survive?

Minimum survivable temperature is roughly above about 15 °C (warm, never cold). Langsat has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is langsat?

Langsat is rated USDA 10b–12 and RHS H1a — Tropical — needs a heated room or greenhouse; no frost tolerance whatsoever.

Can langsat survive winter outside?

It can holiday outdoors in summer once nights are reliably above above 15 °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 langsat below its minimum temperature?

Below about above about 15 °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.