Cold hardiness & minimum temperature

Is Scarlet Sage (Salvia splendens)cold hardy? Hardiness zone & min temp

Also called Scarlet Sage, Red Sage, Fire Sage, Tropical Sage.

More about scarlet sage

About Scarlet Sage

Salvia splendens · also called Scarlet Sage, Red Sage · flowering

Salvia splendens is a tender perennial native to shaded forest margins in Brazil, grown almost universally as a bedding annual in temperate climates for its densely packed, brilliantly coloured flower spikes in red, pink, white, coral, and purple. It is one of the most widely planted summer bedding plants in the world, reliably flowering from late spring until the first autumn frost. The single most important care fact is that it needs consistent moisture — it will not tolerate drought and quickly drops flower buds if the soil dries out. Research has documented anticoagulant activity of plant extracts in dogs; classified as mildly-toxic as a precaution.

Cold limit: USDA 10–11 (grown as annual in zones 3–9) · RHS H1c (10–30°C)

What scarlet sage's hardiness rating actually means

Hardiness works differently for scarlet sage: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10–11 (grown as annual in zones 3–9) — 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

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

Concretely, for scarlet sage as it gets too cold:

Light frost (around 0 to −2 °C) damages or kills tender summer crops outright; cold-hardy types take a few degrees of frost.
The plant does not "survive winter" — its life cycle simply ends, by design, when frost arrives or it finishes cropping.
A surprise late spring frost can also kill young transplants set out too early, before the season even starts.

Can scarlet sage go outside or overwinter — and where?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost.
In short-season zones, start it indoors or under cover to stretch the effective growing window.
Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

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 scarlet sage can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline scarlet sage

Scarlet Sage is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks.
Have row cover ready for an unexpected late spring or early autumn frost.
Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.

Scarlet Sage hardiness — frequently asked questions

Is scarlet sage cold hardy?

Hardiness works differently for scarlet sage: it is grown as a seasonal crop, not overwintered. The question is not "what zone" but "how long is your frost-free growing window". A seasonal crop, not a perennial. Scarlet Sage is grown 10–11 (grown as annual in zones 3–9); you sow after the last frost and harvest before the first one, then start again next year.

What is the minimum temperature scarlet sage can survive?

As an annual crop, its "minimum temperature" is the first hard frost — that is the end of the plant's life, not a survivable low. Many types are also damaged by light frost (around 0 °C).

What hardiness zone is scarlet sage?

Scarlet Sage is rated USDA 10–11 (grown as annual in zones 3–9) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can scarlet sage survive winter outside?

Time it to your frost dates: sow or plant out after the last spring frost, and aim to harvest before the first autumn frost. In short-season zones, start it indoors or under cover to stretch the effective growing window. Hardier crops in this group can be sown for an autumn or overwintered harvest in mild zones — check the specific crop.

How do I protect scarlet sage from frost?

Use fleece, cloches or a cold frame at each end of the season to dodge a borderline frost and add growing weeks. Have row cover ready for an unexpected late spring or early autumn frost. Know your local last- and first-frost dates and count back the crop’s days-to-maturity to schedule the sowing.