Cold hardiness & minimum temperature

Is Coreopsis 'Jethro Tull' (Coreopsis 'Jethro Tull')cold hardy? Hardiness zone & min temp

Also called Jethro Tull Tickseed, Flute Coreopsis.

More about coreopsis 'jethro tull'

About Coreopsis 'Jethro Tull'

Coreopsis 'Jethro Tull' · also called Jethro Tull Tickseed, Flute Coreopsis · flowering

Coreopsis 'Jethro Tull' is a distinctive perennial tickseed with uniquely tubular, quilled golden-yellow petals that give its flowers a flute-like appearance. It blooms from late spring through summer, forming a compact mound of attractive foliage. Best in full sun with excellent drainage. Coreopsis is non-toxic to dogs and cats per the ASPCA.

Cold limit: USDA 4-9 · RHS H5 (-10-30°C)

What coreopsis 'jethro tull''s hardiness rating actually means

Yes — coreopsis 'jethro tull' is genuinely cold hardy. Rated RHS H5 and USDA 4-9, 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 4-9 — 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 'Jethro Tull' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for coreopsis 'jethro tull' 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 'jethro tull' go outside or overwinter — and where?

Plant it out within USDA 4-9 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 'jethro tull' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Coreopsis 'Jethro Tull' hardiness — frequently asked questions

Is coreopsis 'jethro tull' cold hardy?

Yes — coreopsis 'jethro tull' is genuinely cold hardy. Rated RHS H5 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Coreopsis 'Jethro Tull' is hardy across USDA 4-9; 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 'jethro tull' can survive?

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

What hardiness zone is coreopsis 'jethro tull'?

Coreopsis 'Jethro Tull' is rated USDA 4-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can coreopsis 'jethro tull' survive winter outside?

Plant it out within USDA 4-9 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 'jethro tull' 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.