Cold hardiness & minimum temperature

Is Plumed cockscomb (Celosia argentea var. plumosa)cold hardy? Hardiness zone & min temp

Also called plumed cockscomb, feather celosia, plume celosia, wheat celosia, Prince of Wales feather.

More about plumed cockscomb

About Plumed cockscomb

Celosia argentea var. plumosa · also called plumed cockscomb, feather celosia · flowering

Plumed cockscomb is a bold warm-season annual grown for its feathery, flame-like plumes of scarlet, orange, yellow, pink or bicolour flowers above strong upright stems. Easier to grow than the crested form, it tolerates more heat and humidity. It thrives in full sun and well-drained soil and is excellent for beds, borders, containers and long-lasting cut flowers. ASPCA-listed as non-toxic.

Cold limit: USDA 10-11 (grown as a warm-season annual in zones 2-9) · RHS H2 (18-32°C)

Watch for — Root rot from cold, wet soil: Planting out before soil temperatures reach 15°C or waterlogging causes basal stem and root rot — wait until conditions are warm and settled before transplanting, and ensure sharp drainage.

What plumed cockscomb's hardiness rating actually means

Hardiness works differently for plumed cockscomb: 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 H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 10-11 (grown as a warm-season annual in zones 2-9) — 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 plumed cockscomb 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 plumed cockscomb 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 plumed cockscomb can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline plumed cockscomb

Plumed cockscomb 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.

Plumed cockscomb hardiness — frequently asked questions

Is plumed cockscomb cold hardy?

Hardiness works differently for plumed cockscomb: 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. Plumed cockscomb is grown 10-11 (grown as a warm-season annual in zones 2-9); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature plumed cockscomb 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 plumed cockscomb?

Plumed cockscomb is rated USDA 10-11 (grown as a warm-season annual in zones 2-9) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can plumed cockscomb 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 plumed cockscomb 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.