Cold hardiness & minimum temperature

Is Plains Coreopsis (Coreopsis tinctoria)cold hardy? Hardiness zone & min temp

Also called Plains Coreopsis, Golden Tickseed, Calliopsis, Annual Coreopsis.

More about plains coreopsis

About Plains Coreopsis

Coreopsis tinctoria · also called Plains Coreopsis, Golden Tickseed · flowering

Plains Coreopsis is a fast-growing annual wildflower native to the central US, bearing bright yellow-and-red bicolored daisy-like blooms from summer into fall. Extremely drought-tolerant once established, it thrives in poor soils and full sun, self-sows prolifically, and is a magnet for bees, butterflies, and goldfinches.

Cold limit: USDA 2-11 (grown as annual) · RHS H7 (hardy annual) (10–35°C)

What plains coreopsis's hardiness rating actually means

Yes — plains coreopsis is genuinely cold hardy. Rated RHS H7 and USDA 2-11 (grown as annual), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 2-11 (grown as annual) — 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 below about −20 °C. Plains Coreopsis is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for plains coreopsis as it gets too cold:

It tolerates winter lows to about −20 °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 plains coreopsis go outside or overwinter — and where?

Plant it out within USDA 2-11 (grown as annual) 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 plains coreopsis can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Plains Coreopsis hardiness — frequently asked questions

Is plains coreopsis cold hardy?

Yes — plains coreopsis is genuinely cold hardy. Rated RHS H7 and USDA 2-11 (grown as annual), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Plains Coreopsis is hardy across USDA 2-11 (grown as annual); 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 plains coreopsis can survive?

Minimum survivable temperature is roughly below about −20 °C. Plains Coreopsis is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is plains coreopsis?

Plains Coreopsis is rated USDA 2-11 (grown as annual) and RHS H7 — Hardy in the severest European continental winters.

Can plains coreopsis survive winter outside?

Plant it out within USDA 2-11 (grown as annual) 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 plains coreopsis below its minimum temperature?

It tolerates winter lows to about −20 °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.