Cold hardiness & minimum temperature

Is Aquilegia 'Black Barlow' (Aquilegia vulgaris 'Black Barlow')cold hardy? Hardiness zone & min temp

Also called Black Barlow columbine, granny's bonnet.

More about aquilegia 'black barlow'

About Aquilegia 'Black Barlow'

Aquilegia vulgaris 'Black Barlow' · also called Black Barlow columbine, granny's bonnet · flowering

Aquilegia vulgaris 'Black Barlow' is a striking double columbine with fully filled, spurless pompom flowers in deep maroon-black, held on tall stems above blue-green ferny foliage in late spring. A vigorous cottage-garden perennial, it thrives in sun to part shade and moist, well-drained soil, and self-seeds to form dramatic dark clumps.

Cold limit: USDA 3-8 · RHS H7 (13-24°C)

Watch for — Crown rot in wet ground: Heavy, waterlogged winter soil rots the crown. Plant in well-drained soil and avoid sites where water sits to ensure the clump survives cold, wet seasons.

What aquilegia 'black barlow''s hardiness rating actually means

Yes — aquilegia 'black barlow' is genuinely cold hardy. Rated RHS H7 and USDA 3-8, 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 3-8 — 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. Aquilegia 'Black Barlow' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for aquilegia 'black barlow' 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 aquilegia 'black barlow' go outside or overwinter — and where?

Plant it out within USDA 3-8 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 aquilegia 'black barlow' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Aquilegia 'Black Barlow' hardiness — frequently asked questions

Is aquilegia 'black barlow' cold hardy?

Yes — aquilegia 'black barlow' is genuinely cold hardy. Rated RHS H7 and USDA 3-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Aquilegia 'Black Barlow' is hardy across USDA 3-8; 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 aquilegia 'black barlow' can survive?

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

What hardiness zone is aquilegia 'black barlow'?

Aquilegia 'Black Barlow' is rated USDA 3-8 and RHS H7 — Hardy in the severest European continental winters.

Can aquilegia 'black barlow' survive winter outside?

Plant it out within USDA 3-8 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 aquilegia 'black barlow' 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.