Cold hardiness & minimum temperature

Is White laceflower (Orlaya grandiflora)cold hardy? Hardiness zone & min temp

Also called White laceflower, White lace flower, Orlaya.

More about white laceflower

About White laceflower

Orlaya grandiflora · also called White laceflower, White lace flower · flowering

White laceflower is a hardy annual from the Mediterranean producing elegant, flat-topped umbels of brilliant white flowers with notably enlarged outer petals, creating a lace-like effect above finely cut, feathery foliage. Outstanding as a cut flower and garden annual; autumn sowing produces stronger plants with longer stems. Self-sows reliably. Full sun and well-drained soil essential.

Cold limit: USDA 5-9 · RHS H5 (5–22°C)

Watch for — Poor germination when sown in spring: Seeds have complex dormancy and germinate best after a cold, moist period (natural stratification). Autumn sowing in situ or refrigerated stratification for 4–6 weeks before spring sowing dramatically improves germination rates.

What white laceflower's hardiness rating actually means

Yes — white laceflower is genuinely cold hardy. Rated RHS H5 and USDA 5-9, 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 5-9 — 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. White laceflower is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for white laceflower 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 white laceflower go outside or overwinter — and where?

Plant it out within USDA 5-9 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 white laceflower can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

White laceflower hardiness — frequently asked questions

Is white laceflower cold hardy?

Yes — white laceflower is genuinely cold hardy. Rated RHS H5 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. White laceflower is hardy across USDA 5-9; 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 white laceflower can survive?

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

What hardiness zone is white laceflower?

White laceflower is rated USDA 5-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can white laceflower survive winter outside?

Plant it out within USDA 5-9 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 white laceflower 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.