Cold hardiness & minimum temperature

Is Red Feather Clover (Trifolium rubens)cold hardy? Hardiness zone & min temp

Also called Red Feather Clover, Ruddy Clover, Ornamental Clover.

More about red feather clover

About Red Feather Clover

Trifolium rubens · also called Red Feather Clover, Ruddy Clover · flowering

Trifolium rubens is a clump-forming herbaceous perennial native to central and southern Europe, prized in ornamental gardens for its tall, cylindrical spikes of deep crimson-purple flowers that appear from late spring to late summer. It thrives in full sun to light shade in well-drained, poor to moderately fertile soil, and is notably drought-tolerant once established. The most important care fact is that winter waterlogging is the primary killer — sharp drainage is essential to maintain longevity. Red Feather Clover is considered non-toxic to cats and dogs.

Cold limit: USDA 5-8 · RHS H7 (-20 to 28°C)

Watch for — Winter wet crown rot: Prolonged waterlogging of the crown in cold, wet winters is the leading cause of plant loss; ensure sharp drainage and consider adding grit when planting on heavy soils. On borderline-draining sites, plant on a slight slope or raised bed.

What red feather clover's hardiness rating actually means

Yes — red feather clover is genuinely cold hardy. Rated RHS H7 and USDA 5-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 5-8 — 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 below about −20 °C. Red Feather Clover is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for red feather clover as it gets too cold:

It tolerates winter lows to about −20 °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 red feather clover go outside or overwinter — and where?

Plant it out within USDA 5-8 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 red feather clover can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Red Feather Clover hardiness — frequently asked questions

Is red feather clover cold hardy?

Yes — red feather clover is genuinely cold hardy. Rated RHS H7 and USDA 5-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Red Feather Clover is hardy across USDA 5-8; 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 red feather clover can survive?

Minimum survivable temperature is roughly below about −20 °C. Red Feather Clover is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is red feather clover?

Red Feather Clover is rated USDA 5-8 and RHS H7 — Hardy in the severest European continental winters.

Can red feather clover survive winter outside?

Plant it out within USDA 5-8 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 red feather clover below its minimum temperature?

It tolerates winter lows to about −20 °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.