Cold hardiness & minimum temperature

Is Camphor Thyme (Thymus camphoratus)cold hardy? Hardiness zone & min temp

Also called Camphor Thyme, Portuguese Thyme.

More about camphor thyme

About Camphor Thyme

Thymus camphoratus · also called Camphor Thyme, Portuguese Thyme · herb

Camphor Thyme is a compact, grey-leaved Mediterranean species from Portugal with a strong, distinctive camphor-pine scent rather than the culinary thyme aroma. It forms a small neat mound covered in pink-purple flowers in summer. Grown mainly as an ornamental and insect-repellent herb, it demands excellent drainage and full sun.

Cold limit: USDA 7–10 · RHS H4 (-5–35°C)

Watch for — Crown rot in wet conditions: The primary cause of death — winter rainfall on heavy or clay soil causes rapid crown collapse. Plant in raised beds, on slopes, or in containers with excellent drainage; mulch with grit rather than organic material.

What camphor thyme's hardiness rating actually means

Yes — camphor thyme is genuinely cold hardy. Rated RHS H4 and USDA 7–10, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 7–10 — 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 −10 to −5 °C. Camphor Thyme is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for camphor thyme as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 camphor thyme go outside or overwinter — and where?

Plant it out within USDA 7–10 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 camphor thyme can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Camphor Thyme hardiness — frequently asked questions

Is camphor thyme cold hardy?

Yes — camphor thyme is genuinely cold hardy. Rated RHS H4 and USDA 7–10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Camphor Thyme is hardy across USDA 7–10; 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 camphor thyme can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Camphor Thyme is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is camphor thyme?

Camphor Thyme is rated USDA 7–10 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can camphor thyme survive winter outside?

Plant it out within USDA 7–10 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 camphor thyme below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.