Cold hardiness & minimum temperature

Is Intermediate Polypody (Polypodium interjectum)cold hardy? Hardiness zone & min temp

Also called Intermediate Polypody, Intermediate Polypod.

More about intermediate polypody

About Intermediate Polypody

Polypodium interjectum · also called Intermediate Polypody, Intermediate Polypod · houseplant

Intermediate Polypody is a native British and European fern that grows wild on shaded walls, cliffs, and hedgebanks. Its leathery, deeply pinnatifid fronds are evergreen and unfussy, making it an excellent choice for cool, shaded windowsills or outdoor rock gardens in the UK. It is hardier than many houseplant ferns and withstands light frost.

Cold limit: USDA 5-9 · RHS H6 (0–20°C)

What intermediate polypody's hardiness rating actually means

Yes — intermediate polypody is genuinely cold hardy. Rated RHS H6 and USDA 5-9, 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 5-9 — 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. Intermediate Polypody is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for intermediate polypody 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 intermediate polypody go outside or overwinter — and where?

Plant it out within USDA 5-9 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 intermediate polypody can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Intermediate Polypody hardiness — frequently asked questions

Is intermediate polypody cold hardy?

Yes — intermediate polypody is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Intermediate Polypody is hardy across USDA 5-9; 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 intermediate polypody can survive?

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

What hardiness zone is intermediate polypody?

Intermediate Polypody is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can intermediate polypody survive winter outside?

Plant it out within USDA 5-9 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 intermediate polypody 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.