Cold hardiness & minimum temperature

Is Coreopsis 'Ruby Sunset' (Coreopsis 'Ruby Sunset')cold hardy? Hardiness zone & min temp

Also called Tickseed 'Ruby Sunset', Ruby Tickseed.

More about coreopsis 'ruby sunset'

About Coreopsis 'Ruby Sunset'

Coreopsis 'Ruby Sunset' · also called Tickseed 'Ruby Sunset', Ruby Tickseed · flowering

A vibrant hybrid tickseed bearing rich ruby-red, semi-double daisy flowers through summer and into autumn. Forms a tidy, low mound of fine-textured foliage. Heat and drought tolerant once established. A long-blooming perennial that attracts butterflies and bees. Not listed as toxic by the ASPCA.

Cold limit: USDA 5-9 · RHS H5 (−20 to 35°C)

Watch for — Crown rot: The most common issue; caused by wet or waterlogged soil, especially in winter. Ensure excellent drainage and avoid mulching directly against the crown.

What coreopsis 'ruby sunset''s hardiness rating actually means

Yes — coreopsis 'ruby sunset' is genuinely cold hardy. Rated RHS H5 and USDA 5-9, 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 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 −15 to −10 °C. Coreopsis 'Ruby Sunset' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for coreopsis 'ruby sunset' 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 coreopsis 'ruby sunset' 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 coreopsis 'ruby sunset' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Coreopsis 'Ruby Sunset' hardiness — frequently asked questions

Is coreopsis 'ruby sunset' cold hardy?

Yes — coreopsis 'ruby sunset' is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Coreopsis 'Ruby Sunset' 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 coreopsis 'ruby sunset' can survive?

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

What hardiness zone is coreopsis 'ruby sunset'?

Coreopsis 'Ruby Sunset' is rated USDA 5-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can coreopsis 'ruby sunset' 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 coreopsis 'ruby sunset' 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.