Cold hardiness & minimum temperature

Is Greater Coreopsis (Coreopsis major)cold hardy? Hardiness zone & min temp

Also called Greater Coreopsis, Wood Tickseed, Large-flower Tickseed.

More about greater coreopsis

About Greater Coreopsis

Coreopsis major · also called Greater Coreopsis, Wood Tickseed · flowering

Greater Coreopsis is a perennial native to open woodlands and pine barrens of the eastern and southeastern US. It bears bright yellow flowers with a distinctive whorled leaf arrangement on upright stems from early to mid-summer. Unlike most coreopsis, it tolerates partial shade, making it useful in dry, open woodland gardens and naturalistic plantings.

Cold limit: USDA 5-9 · RHS H6 (-20–38°C)

Watch for — Root rot in heavy soils: Heavy clay or consistently wet soils cause crown rot, particularly over wet winters. Improve drainage with grit, or site on a gentle slope. This species is not suited to rain gardens.

What greater coreopsis's hardiness rating actually means

Yes — greater coreopsis is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 5-9 — 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 −20 to −15 °C. Greater Coreopsis is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for greater coreopsis as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 greater coreopsis go outside or overwinter — and where?

Plant it out within USDA 5-9 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 greater coreopsis can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Greater Coreopsis hardiness — frequently asked questions

Is greater coreopsis cold hardy?

Yes — greater coreopsis is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Greater Coreopsis is hardy across USDA 5-9; 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 greater coreopsis can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Greater Coreopsis is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is greater coreopsis?

Greater Coreopsis is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can greater coreopsis survive winter outside?

Plant it out within USDA 5-9 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 greater coreopsis below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.