Cold hardiness & minimum temperature

Is Blanket flower (Gaillardia x grandiflora)cold hardy? Hardiness zone & min temp

Also called Blanket flower, Great blanket flower.

More about blanket flower

About Blanket flower

Gaillardia x grandiflora · also called Blanket flower, Great blanket flower · flowering

A sun-loving, drought-tolerant perennial producing vivid daisy-like flowers in bold combinations of red, orange, and yellow from early summer right through to the first frosts. Outstanding prairie and xeriscape plant. Pet-safe per ASPCA. Requires excellent drainage to persist; tends to be short-lived in heavy, wet soils but reseeds readily.

Cold limit: USDA 3-9 · RHS H5 (-20 to 38°C)

What blanket flower's hardiness rating actually means

Yes — blanket flower is genuinely cold hardy. Rated RHS H5 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 3-9 — 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

Minimum survivable temperature is roughly about −15 to −10 °C. Blanket flower is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for blanket flower as it gets too cold:

It tolerates winter lows to about −15 to −10 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can blanket flower go outside or overwinter — and where?

Plant it out within USDA 3-9 and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

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 blanket flower can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Blanket flower hardiness — frequently asked questions

Is blanket flower cold hardy?

Yes — blanket flower is genuinely cold hardy. Rated RHS H5 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Blanket flower is hardy across USDA 3-9; it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature blanket flower can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Blanket flower is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is blanket flower?

Blanket flower is rated USDA 3-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can blanket flower survive winter outside?

Plant it out within USDA 3-9 and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to blanket flower below its minimum temperature?

It tolerates winter lows to about −15 to −10 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.