Cold hardiness & minimum temperature

Is Physocarpus opulifolius 'Diabolo' (Physocarpus opulifolius 'Monlo' (Diabolo))cold hardy? Hardiness zone & min temp

Also called Diabolo ninebark, purple ninebark Diabolo.

More about physocarpus opulifolius 'diabolo'

About Physocarpus opulifolius 'Diabolo'

Physocarpus opulifolius 'Monlo' (Diabolo) · also called Diabolo ninebark, purple ninebark Diabolo · flowering

'Diabolo' is the classic dark-leaved ninebark, with deep maroon-purple foliage that sets off clusters of pinkish-white early-summer flowers and red seed heads. An extremely hardy, adaptable North American native shrub with peeling 'nine-bark' stems. It thrives in full sun on almost any soil and earns an RHS Award of Garden Merit for reliability and colour.

Cold limit: USDA 3-7 · RHS H7 (-37 to 32°C)

Watch for — Large, sprawling, bare-based habit: Old plants flop open and go woody at the base. Cut a third of the oldest stems to ground level each winter, or coppice hard, to renew dense growth.

What physocarpus opulifolius 'diabolo''s hardiness rating actually means

Yes — physocarpus opulifolius 'diabolo' is genuinely cold hardy. Rated RHS H7 and USDA 3-7, 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 3-7 — 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. Physocarpus opulifolius 'Diabolo' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for physocarpus opulifolius 'diabolo' 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 physocarpus opulifolius 'diabolo' go outside or overwinter — and where?

Plant it out within USDA 3-7 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 physocarpus opulifolius 'diabolo' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Physocarpus opulifolius 'Diabolo' hardiness — frequently asked questions

Is physocarpus opulifolius 'diabolo' cold hardy?

Yes — physocarpus opulifolius 'diabolo' is genuinely cold hardy. Rated RHS H7 and USDA 3-7, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Physocarpus opulifolius 'Diabolo' is hardy across USDA 3-7; 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 physocarpus opulifolius 'diabolo' can survive?

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

What hardiness zone is physocarpus opulifolius 'diabolo'?

Physocarpus opulifolius 'Diabolo' is rated USDA 3-7 and RHS H7 — Hardy in the severest European continental winters.

Can physocarpus opulifolius 'diabolo' survive winter outside?

Plant it out within USDA 3-7 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 physocarpus opulifolius 'diabolo' 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.