Cold hardiness & minimum temperature

Is Paulownia tomentosa (Paulownia tomentosa)cold hardy? Hardiness zone & min temp

Also called Foxglove Tree, Empress Tree, Princess Tree.

More about paulownia tomentosa

About Paulownia tomentosa

Paulownia tomentosa · also called Foxglove Tree, Empress Tree · flowering

An extremely fast-growing tree prized for enormous, fuzzy heart-shaped leaves and upright panicles of fragrant, foxglove-like lilac flowers that open before the foliage in spring. Often pollarded for giant decorative leaves. Note it is highly invasive in parts of North America, so check local guidance before planting.

Cold limit: USDA 5-9 · RHS H5 (-23 to 38°C)

Watch for — Frost-killed flower buds: Flower buds form in autumn and overwinter on bare stems; a hard frost or cold spring often destroys them, so blooming is unreliable in colder areas. The tree itself usually survives.

What paulownia tomentosa's hardiness rating actually means

Yes — paulownia tomentosa is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. 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 −15 to −10 °C. Paulownia tomentosa is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for paulownia tomentosa as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 paulownia tomentosa 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 paulownia tomentosa can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Paulownia tomentosa hardiness — frequently asked questions

Is paulownia tomentosa cold hardy?

Yes — paulownia tomentosa is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Paulownia tomentosa 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 paulownia tomentosa can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Paulownia tomentosa is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is paulownia tomentosa?

Paulownia tomentosa is rated USDA 5-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can paulownia tomentosa 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 paulownia tomentosa below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.