Cold hardiness & minimum temperature

Is feather grass (Stipa barbata)cold hardy? Hardiness zone & min temp

Also called feather grass, silver feather grass, bearded feather grass.

More about feather grass

About feather grass

Stipa barbata · also called feather grass, silver feather grass · flowering

Feather grass is a graceful short-lived perennial from southern Europe and western Asia, forming dense clumps of slender upright foliage. Its extraordinarily long, silky, silver-white twisted awns — up to 30 cm — dance in the breeze from late spring to early summer, creating a shimmering effect unmatched among ornamental grasses. Thrives in full sun and sharply drained soil.

Cold limit: USDA 6–10 · RHS H6 (-20–38°C)

Watch for — Crown rot in winter wet: Prolonged wet conditions in winter, especially on heavy soils, causes crown rot. Sharp drainage is critical. Plant in gravel beds or raised areas; never in waterlogged ground. Reduce or eliminate irrigation from mid-autumn through early spring.

What feather grass's hardiness rating actually means

Yes — feather grass is genuinely cold hardy. Rated RHS H6 and USDA 6–10, 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 6–10 — 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. feather grass is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for feather grass 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 feather grass go outside or overwinter — and where?

Plant it out within USDA 6–10 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 feather grass can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

feather grass hardiness — frequently asked questions

Is feather grass cold hardy?

Yes — feather grass is genuinely cold hardy. Rated RHS H6 and USDA 6–10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. feather grass is hardy across USDA 6–10; 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 feather grass can survive?

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

What hardiness zone is feather grass?

feather grass is rated USDA 6–10 and RHS H6 — Hardy throughout the UK and northern Europe.

Can feather grass survive winter outside?

Plant it out within USDA 6–10 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 feather grass 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.