Cold hardiness & minimum temperature

Is Weld (Reseda luteola)cold hardy? Hardiness zone & min temp

Also called Weld, Dyer's Rocket, Wild Mignonette, Dyer's Weed.

More about weld

About Weld

Reseda luteola · also called Weld, Dyer's Rocket · herb

Reseda luteola is an erect biennial (occasionally annual) native to chalky, disturbed ground, roadsides, and quarry spoil across Europe and the Mediterranean, long cultivated as the most important yellow natural dye plant in European history; its stems and leaves yield luteolin and apigenin, producing fast, brilliant yellows on wool and silk. In the first year it forms a low, wavy-edged basal rosette; in its second year it bolts to a tall, unbranched spike packed with tiny yellowish-green flowers attractive to bees and hoverflies. It demands full sun, sharply drained alkaline soil, and minimal fertility to maintain its characteristic upright habit. Weld is not known to be toxic to cats or dogs.

Cold limit: USDA 4-8 · RHS H6 (-20 °C to 30 °C)

What weld's hardiness rating actually means

Yes — weld is genuinely cold hardy. Rated RHS H6 and USDA 4-8, 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 4-8 — 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. Weld is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for weld 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 weld go outside or overwinter — and where?

Plant it out within USDA 4-8 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 weld can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Weld hardiness — frequently asked questions

Is weld cold hardy?

Yes — weld is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Weld is hardy across USDA 4-8; 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 weld can survive?

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

What hardiness zone is weld?

Weld is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can weld survive winter outside?

Plant it out within USDA 4-8 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 weld 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.