Cold hardiness & minimum temperature

Is Pretty Face (Triteleia ixioides)cold hardy? Hardiness zone & min temp

Also called Golden Brodiaea, Yellow Triteleia, Fool's Onion.

More about pretty face

About Pretty Face

Triteleia ixioides · also called Golden Brodiaea, Yellow Triteleia · flowering

Pretty Face is a California native corm producing cheerful yellow star-shaped flowers with a darker midrib stripe in late spring and early summer. It thrives in dry, well-drained soils and naturalises freely in Mediterranean-climate borders. Goes dormant in summer. Not listed as toxic by the ASPCA; considered pet-safe.

Cold limit: USDA 6-10 · RHS H5 (5-25°C)

Watch for — Failure to flower: Usually the result of too much shade or insufficient chilling period. Ensure full sun and allow the corm a dry cold rest in winter.

What pretty face's hardiness rating actually means

Yes — pretty face is genuinely cold hardy. Rated RHS H5 and USDA 6-10, 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 6-10 — 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 −15 to −10 °C. Pretty Face is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for pretty face 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 pretty face go outside or overwinter — and where?

Plant it out within USDA 6-10 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 pretty face can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Pretty Face hardiness — frequently asked questions

Is pretty face cold hardy?

Yes — pretty face is genuinely cold hardy. Rated RHS H5 and USDA 6-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Pretty Face is hardy across USDA 6-10; 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 pretty face can survive?

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

What hardiness zone is pretty face?

Pretty Face is rated USDA 6-10 and RHS H5 — Hardy in most of the UK and in cold winters.

Can pretty face survive winter outside?

Plant it out within USDA 6-10 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 pretty face 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.