Cold hardiness & minimum temperature

Is Summit Sage (Salvia summa)cold hardy? Hardiness zone & min temp

Also called Summit sage, Supreme sage, Great sage.

More about summit sage

About Summit Sage

Salvia summa · also called Summit sage, Supreme sage · flowering

Salvia summa is a rare, compact herbaceous perennial native to a small area of limestone cliffs in southern New Mexico, adjacent northern Texas, and Chihuahua, Mexico, growing at elevations of 1,520–2,140 m in partial shade. It produces relatively large, pink to pale-lavender flowers spotted with red in the throat on a plant that reaches only about 30 cm tall, flowering in spring (March–April). Because of its specialised cliff habitat and very restricted natural range it is considered a rare plant. The ASPCA lists Salvia as non-toxic to cats and dogs.

Cold limit: USDA 6-9 · RHS H5 (-15–30 °C)

What summit sage's hardiness rating actually means

Yes — summit sage is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 6-9 — 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 −15 to −10 °C. Summit Sage is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for summit sage as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 summit sage go outside or overwinter — and where?

Plant it out within USDA 6-9 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 summit sage can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Summit Sage hardiness — frequently asked questions

Is summit sage cold hardy?

Yes — summit sage is genuinely cold hardy. Rated RHS H5 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Summit Sage is hardy across USDA 6-9; 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 summit sage can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Summit Sage is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is summit sage?

Summit Sage is rated USDA 6-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can summit sage survive winter outside?

Plant it out within USDA 6-9 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 summit sage below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.