Cold hardiness & minimum temperature

Is Cloud Nine Dogwood (Cornus florida 'Cloud Nine')cold hardy? Hardiness zone & min temp

Also called Cloud Nine Dogwood, Cloud Nine Flowering Dogwood.

More about cloud nine dogwood

About Cloud Nine Dogwood

Cornus florida 'Cloud Nine' · also called Cloud Nine Dogwood, Cloud Nine Flowering Dogwood · flowering

Cloud Nine Dogwood is a compact, floriferous cultivar of the Eastern Flowering Dogwood, producing exceptionally large white bracts in spring even on young plants. It offers attractive red autumn foliage and red berries. Best suited to part shade with moist, acidic soil; it is more cold-tolerant and blooms earlier than many C. florida selections.

Cold limit: USDA 5-9 · RHS H6 (-23 to 32°C)

What cloud nine dogwood's hardiness rating actually means

Yes — cloud nine dogwood 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. Cloud Nine Dogwood is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for cloud nine dogwood 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 cloud nine dogwood 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 cloud nine dogwood can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Cloud Nine Dogwood hardiness — frequently asked questions

Is cloud nine dogwood cold hardy?

Yes — cloud nine dogwood 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. Cloud Nine Dogwood 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 cloud nine dogwood can survive?

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

What hardiness zone is cloud nine dogwood?

Cloud Nine Dogwood is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can cloud nine dogwood 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 cloud nine dogwood 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.