Cold hardiness & minimum temperature

Is Hooker's Inula (Inula hookeri)cold hardy? Hardiness zone & min temp

Also called Hooker's Inula, Hooker Inula.

More about hooker's inula

About Hooker's Inula

Inula hookeri · also called Hooker's Inula, Hooker Inula · flowering

Hooker's Inula is a vigorous, spreading herbaceous perennial from the Himalayas, valued for its abundant pale yellow daisy flowers with very fine, almost thread-like ray petals giving a shaggy, elegant appearance. It forms spreading colonies in moist, fertile borders, blooming prolifically from late summer into autumn and attracting numerous pollinators.

Cold limit: USDA 4-8 · RHS H6 (-15-28°C)

What hooker's inula's hardiness rating actually means

Yes — hooker's inula is genuinely cold hardy. Rated RHS H6 and USDA 4-8, 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 4-8 — 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. Hooker's Inula is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for hooker's inula 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 hooker's inula go outside or overwinter — and where?

Plant it out within USDA 4-8 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 hooker's inula can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Hooker's Inula hardiness — frequently asked questions

Is hooker's inula cold hardy?

Yes — hooker's inula is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Hooker's Inula is hardy across USDA 4-8; 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 hooker's inula can survive?

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

What hardiness zone is hooker's inula?

Hooker's Inula is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can hooker's inula survive winter outside?

Plant it out within USDA 4-8 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 hooker's inula 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.