Cold hardiness & minimum temperature

Is Licorice Basil (Ocimum basilicum 'Licorice')cold hardy? Hardiness zone & min temp

Also called Licorice Basil, Anise Basil.

More about licorice basil

About Licorice Basil

Ocimum basilicum 'Licorice' · also called Licorice Basil, Anise Basil · herb

Licorice basil is an aromatic, tender annual cultivar of sweet basil with a strong anise-licorice fragrance, purple-flushed stems, and pink-tinged flower spikes. It is grown like any culinary basil, needing warmth, full sun, and steady moisture, and it crops best when pinched regularly. Frost-sensitive, it thrives in summer beds, containers, and warm windowsills.

Cold limit: USDA Grown as a warm-season annual; perennial only in frost-free zones 10-11 · RHS H1c (18-28°C)

Watch for — Cold damage and blackening: Basil is highly frost-tender; temperatures below about 10°C blacken leaves. Plant out only after frosts, and bring containers in or take cuttings before cold nights.

What licorice basil's hardiness rating actually means

Licorice Basil 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 H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA Grown as a warm-season annual; perennial only in frost-free zones 10-11 — 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 5 °C (and never frost). Licorice Basil has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for licorice basil as it gets too cold:

Below about about 5 °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 licorice basil go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °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 licorice basil can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Licorice Basil hardiness — frequently asked questions

Is licorice basil cold hardy?

Licorice Basil 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. Licorice Basil can only live outside year-round in genuinely frost-free climates (roughly USDA Grown as a warm-season annual; perennial only in frost-free zones 10-11); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature licorice basil can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Licorice Basil has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is licorice basil?

Licorice Basil is rated USDA Grown as a warm-season annual; perennial only in frost-free zones 10-11 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can licorice basil survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °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 licorice basil below its minimum temperature?

Below about about 5 °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.