Cold hardiness & minimum temperature

Is White Arrow Arum (Peltandra sagittifolia)cold hardy? Hardiness zone & min temp

Also called White Arrow Arum, Spoonflower, White Arrow-arum.

More about white arrow arum

About White Arrow Arum

Peltandra sagittifolia · also called White Arrow Arum, Spoonflower · flowering

A native southeastern US wetland perennial prized for its snowy-white, scoop-shaped spathe and glossy arrow-shaped leaves. It thrives in boggy margins, shallow ponds, and rain gardens. Plant in consistently wet or waterlogged soil in full sun to partial shade; tolerates standing water. Minimal fertiliser needed in rich organic soils. Spreads slowly by offsets.

Cold limit: USDA 5-9 · RHS H5 (5–35°C)

What white arrow arum's hardiness rating actually means

Yes — white arrow arum 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 Arrow Arum is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for white arrow arum 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 arrow arum 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 arrow arum can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

White Arrow Arum hardiness — frequently asked questions

Is white arrow arum cold hardy?

Yes — white arrow arum 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 Arrow Arum 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 arrow arum can survive?

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

What hardiness zone is white arrow arum?

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

Can white arrow arum 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 arrow arum 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.