Cold hardiness & minimum temperature

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

Also called Blue Ridge creeping phlox, creeping phlox, stolon phlox.

More about blue ridge creeping phlox

About Blue Ridge Creeping Phlox

Phlox stolonifera 'Blue Ridge' · also called Blue Ridge creeping phlox, creeping phlox · flowering

A low-growing, semi-evergreen native groundcover from the woodland floors of the Appalachian Mountains, spreading by above-ground stolons that root at the nodes to form dense weed-suppressing mats. It produces clear lavender-blue flowers in April and May, performing best in moist, well-drained, slightly acidic soil with partial shade. The single most important care fact is to ensure good air circulation around the plant, as dense mats in humid conditions are prone to powdery mildew. Phlox is listed by the ASPCA as non-toxic to cats, dogs, and horses.

Cold limit: USDA 4-9 · RHS H6 (-29°C to 35°C (-20°F to 95°F))

What blue ridge creeping phlox's hardiness rating actually means

Yes — blue ridge creeping phlox is genuinely cold hardy. Rated RHS H6 and USDA 4-9, 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 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 about −20 to −15 °C. Blue Ridge Creeping Phlox is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for blue ridge creeping phlox 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 blue ridge creeping phlox 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 blue ridge creeping phlox can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Blue Ridge Creeping Phlox hardiness — frequently asked questions

Is blue ridge creeping phlox cold hardy?

Yes — blue ridge creeping phlox is genuinely cold hardy. Rated RHS H6 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Blue Ridge Creeping Phlox 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 blue ridge creeping phlox can survive?

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

What hardiness zone is blue ridge creeping phlox?

Blue Ridge Creeping Phlox is rated USDA 4-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can blue ridge creeping phlox 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 blue ridge creeping phlox 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.