Cold hardiness & minimum temperature

Is East Indian Lemongrass (Cymbopogon flexuosus)cold hardy? Hardiness zone & min temp

Also called Cochin Grass, Malabar Grass.

More about east indian lemongrass

About East Indian Lemongrass

Cymbopogon flexuosus · also called Cochin Grass, Malabar Grass · herb

East Indian Lemongrass is a tall, clumping tropical grass grown for its strongly lemon-scented stems and the citral-rich essential oil distilled from its leaves. It demands full sun, steady warmth, and rich moist soil, growing fast into an arching fountain. Frost-tender, it is best treated as an annual or overwintered indoors in cool climates.

Cold limit: USDA 9-11 (grown as an annual or overwintered indoors elsewhere) · RHS H1c (20-30°C)

Watch for — Brown, crispy leaf tips: Caused by drying out, cold draughts, or dry indoor air. Keep soil evenly moist, raise warmth and humidity, and trim damaged tips with clean scissors.

What east indian lemongrass's hardiness rating actually means

Hardiness works differently for east indian lemongrass: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". 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 9-11 (grown as an annual or overwintered indoors 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

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

Concretely, for east indian lemongrass as it gets too cold:

Light frost (around 0 to −2 °C) damages or kills tender summer crops outright; cold-hardy types take a few degrees of frost.
The plant does not "survive winter" — its life cycle simply ends, by design, when frost arrives or it finishes cropping.
A surprise late spring frost can also kill young transplants set out too early, before the season even starts.

Can east indian lemongrass go outside or overwinter — and where?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost.
In short-season zones, start it indoors or under cover to stretch the effective growing window.
Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

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 east indian lemongrass can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline east indian lemongrass

East Indian Lemongrass is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks.
Have row cover ready for an unexpected late spring or early autumn frost.
Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.

East Indian Lemongrass hardiness — frequently asked questions

Is east indian lemongrass cold hardy?

Hardiness works differently for east indian lemongrass: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". A seasonal crop, not a perennial. East Indian Lemongrass is grown 9-11 (grown as an annual or overwintered indoors elsewhere); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature east indian lemongrass can survive?

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

What hardiness zone is east indian lemongrass?

East Indian Lemongrass is rated USDA 9-11 (grown as an annual or overwintered indoors elsewhere) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can east indian lemongrass survive winter outside?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost. In short-season zones, start it indoors or under cover to stretch the effective growing window. Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

How do I protect east indian lemongrass from frost?

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks. Have row cover ready for an unexpected late spring or early autumn frost. Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.