Cold hardiness & minimum temperature

Is Creeping Phlox 'Blue Ridge' (Phlox stolonifera)cold hardy? Hardiness zone & min temp

Also called Creeping Phlox, Woodland Phlox, Stoloniferous Phlox.

More about creeping phlox 'blue ridge'

About Creeping Phlox 'Blue Ridge'

Phlox stolonifera · also called Creeping Phlox, Woodland Phlox · flowering

A low, mat-forming shade-tolerant phlox from the eastern US woodlands, bearing lavender-blue flowers in spring on trailing stolons. 'Blue Ridge' is valued for ground cover under trees and on slopes. It is mildly toxic to dogs and cats according to ASPCA guidance on Phlox species.

Cold limit: USDA 4-9 · RHS H7 (-20-28°C)

What creeping phlox 'blue ridge''s hardiness rating actually means

Yes — creeping phlox 'blue ridge' is genuinely cold hardy. Rated RHS H7 and USDA 4-9, 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 4-9 — 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 below about −20 °C. Creeping Phlox 'Blue Ridge' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for creeping phlox 'blue ridge' 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 creeping phlox 'blue ridge' go outside or overwinter — and where?

Plant it out within USDA 4-9 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 creeping phlox 'blue ridge' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Creeping Phlox 'Blue Ridge' hardiness — frequently asked questions

Is creeping phlox 'blue ridge' cold hardy?

Yes — creeping phlox 'blue ridge' is genuinely cold hardy. Rated RHS H7 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Creeping Phlox 'Blue Ridge' is hardy across USDA 4-9; 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 creeping phlox 'blue ridge' can survive?

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

What hardiness zone is creeping phlox 'blue ridge'?

Creeping Phlox 'Blue Ridge' is rated USDA 4-9 and RHS H7 — Hardy in the severest European continental winters.

Can creeping phlox 'blue ridge' survive winter outside?

Plant it out within USDA 4-9 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 creeping phlox 'blue ridge' 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.