Cold hardiness & minimum temperature

Is Small Teasel (Dipsacus pilosus)cold hardy? Hardiness zone & min temp

Also called Small Teasel, Lesser Teasel.

More about small teasel

About Small Teasel

Dipsacus pilosus · also called Small Teasel, Lesser Teasel · flowering

Small teasel is a British and European native biennial found along the shaded edges of damp woodland, hedgerows, and stream banks on calcareous soils. Unlike its larger relative, it prefers partial shade and produces small, white, softly globose flowerheads on stems reaching 1–1.5 m in its second year. It is an excellent choice for naturalising in a wildlife or woodland-edge garden, and the key care note is that it requires consistently moist, neutral to alkaline soil and some overhead shade to thrive. No significant toxicity to dogs or cats has been reported.

Cold limit: USDA 4-8 · RHS H7 (-20°C to 28°C)

What small teasel's hardiness rating actually means

Yes — small teasel is genuinely cold hardy. Rated RHS H7 and USDA 4-8, 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 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 below about −20 °C. Small Teasel is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for small teasel 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 small teasel 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 small teasel can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Small Teasel hardiness — frequently asked questions

Is small teasel cold hardy?

Yes — small teasel is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Small Teasel 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 small teasel can survive?

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

What hardiness zone is small teasel?

Small Teasel is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can small teasel 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 small teasel 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.