Cold hardiness & minimum temperature

Is White Shrimp Plant (Justicia betonica)cold hardy? Hardiness zone & min temp

Also called White Shrimp Plant, Squirrel's Tail, Vásárhelyi's Shrimp Plant.

More about white shrimp plant

About White Shrimp Plant

Justicia betonica · also called White Shrimp Plant, Squirrel's Tail · tropical

Justicia betonica is a vigorous tropical shrub native to tropical Africa and southern Asia, bearing upright spikes of white, purple-veined bracts tipped with small white flowers that give it a distinctive 'squirrel's tail' silhouette. It thrives in tropical and subtropical gardens or indoors in a bright, warm position with consistently moist, well-drained soil. Unlike its Mexican relative the red shrimp plant, it grows more vigorously and can reach shrub proportions in frost-free conditions, so regular pruning is essential to keep it compact. Justicia betonica has not been individually assessed by the ASPCA; out of caution it is classified as mildly-toxic pending confirmation.

Cold limit: USDA 9-11 · RHS H1b (13–30 °C)

What white shrimp plant's hardiness rating actually means

White Shrimp Plant 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 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 10 °C (sustained cold below this is damaging). White Shrimp Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

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

White Shrimp Plant hardiness — frequently asked questions

Is white shrimp plant cold hardy?

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

What is the minimum temperature white shrimp plant can survive?

What hardiness zone is white shrimp plant?

White Shrimp Plant is rated USDA 9-11 and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can white shrimp plant 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 white shrimp plant 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.