Cold hardiness & minimum temperature

Is Candle larkspur (Delphinium elatum)cold hardy? Hardiness zone & min temp

Also called Candle larkspur, Alpine delphinium, Bee larkspur.

More about candle larkspur

About Candle larkspur

Delphinium elatum · also called Candle larkspur, Alpine delphinium · flowering

A tall, stately perennial with majestic, densely packed flower spikes in shades of blue, purple, white, and pink rising to 2 m or more. Native to alpine meadows of Europe and Central Asia, it demands fertile, well-drained soil in full sun and cool summer temperatures. Highly toxic to pets and humans. Requires staking in exposed positions.

Cold limit: USDA 3-7 · RHS H7 (-40 to 22°C)

What candle larkspur's hardiness rating actually means

Yes — candle larkspur 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. Candle larkspur is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for candle larkspur 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 candle larkspur 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 candle larkspur can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Candle larkspur hardiness — frequently asked questions

Is candle larkspur cold hardy?

Yes — candle larkspur 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. Candle larkspur 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 candle larkspur can survive?

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

What hardiness zone is candle larkspur?

Candle larkspur is rated USDA 3-7 and RHS H7 — Hardy in the severest European continental winters.

Can candle larkspur 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 candle larkspur 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.