Cold hardiness & minimum temperature

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

Also called Shrimp Plant, Mexican Shrimp Plant, Shrimp Bush, False Hop.

More about shrimp plant

About Shrimp Plant

Justicia brandegeeana · also called Shrimp Plant, Mexican Shrimp Plant · tropical

Native to Mexico, Justicia brandegeeana is an evergreen shrub grown for its arching chains of overlapping salmon-pink bracts that closely resemble a shrimp, which persist almost year-round when given adequate light. It thrives in bright indirect light with evenly moist, well-drained soil and performs best when pinched back regularly to prevent legginess. The most important care fact is that it will bloom most prolifically and maintain compact growth when given high light and pruned after each flowering flush. According to the ASPCA, Justicia brandegeeana is considered non-toxic to cats and dogs.

Cold limit: USDA 9-11 · RHS H1b (10–27 °C)

What shrimp plant's hardiness rating actually means

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). Shrimp Plant has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for 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 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 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.

Shrimp Plant hardiness — frequently asked questions

Is shrimp plant cold hardy?

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. 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 shrimp plant can survive?

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

What hardiness zone is shrimp plant?

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 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 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.