Cold hardiness & minimum temperature

Is Straw Foxglove (Digitalis lutea)cold hardy? Hardiness zone & min temp

Also called straw foxglove, small yellow foxglove.

More about straw foxglove

About Straw Foxglove

Digitalis lutea · also called straw foxglove, small yellow foxglove · flowering

Straw foxglove is a refined, reliably perennial species with slender spires of small, pale creamy-yellow tubular flowers in summer above neat glossy foliage. More compact and longer-lived than the common foxglove, it suits part-shade borders and woodland edges in moist, well-drained soil. As with all foxgloves, every part is toxic, containing cardiac glycosides.

Cold limit: USDA 4-8 (cold-hardy perennial) · RHS H7 (-29 to 24°C)

Watch for — Crown rot in winter wet: Soggy soil rots the crown over winter. Provide sharp drainage, avoid heavy clay and keep mulch off the immediate crown.

What straw foxglove's hardiness rating actually means

Yes — straw foxglove is genuinely cold hardy. Rated RHS H7 and USDA 4-8 (cold-hardy perennial), 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 (cold-hardy perennial) — 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. Straw Foxglove is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for straw foxglove 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 straw foxglove go outside or overwinter — and where?

Plant it out within USDA 4-8 (cold-hardy perennial) 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 straw foxglove can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Straw Foxglove hardiness — frequently asked questions

Is straw foxglove cold hardy?

Yes — straw foxglove is genuinely cold hardy. Rated RHS H7 and USDA 4-8 (cold-hardy perennial), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Straw Foxglove is hardy across USDA 4-8 (cold-hardy perennial); 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 straw foxglove can survive?

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

What hardiness zone is straw foxglove?

Straw Foxglove is rated USDA 4-8 (cold-hardy perennial) and RHS H7 — Hardy in the severest European continental winters.

Can straw foxglove survive winter outside?

Plant it out within USDA 4-8 (cold-hardy perennial) 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 straw foxglove 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.