Cold hardiness & minimum temperature

Is Ivy-leaved Duckweed (Lemna trisulca)cold hardy? Hardiness zone & min temp

Also called Ivy-leaved Duckweed, Star Duckweed.

More about ivy-leaved duckweed

About Ivy-leaved Duckweed

Lemna trisulca · also called Ivy-leaved Duckweed, Star Duckweed · flowering

Ivy-leaved Duckweed is a distinctive submerged duckweed native to Europe, Asia, and North America, forming translucent pale-green fronds connected in branching chains beneath the water surface. Unlike other duckweeds, it stays submerged until flowering. An excellent oxygenator and fish food plant for wildlife ponds and aquaria. Hardy and low-maintenance.

Cold limit: USDA 4-10 · RHS H7 (4–24°C)

What ivy-leaved duckweed's hardiness rating actually means

Yes — ivy-leaved duckweed is genuinely cold hardy. Rated RHS H7 and USDA 4-10, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 4-10 — 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 below about −20 °C. Ivy-leaved Duckweed is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for ivy-leaved duckweed as it gets too cold:

It tolerates winter lows to about −20 °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 ivy-leaved duckweed go outside or overwinter — and where?

Plant it out within USDA 4-10 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 ivy-leaved duckweed can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Ivy-leaved Duckweed hardiness — frequently asked questions

Is ivy-leaved duckweed cold hardy?

Yes — ivy-leaved duckweed is genuinely cold hardy. Rated RHS H7 and USDA 4-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Ivy-leaved Duckweed is hardy across USDA 4-10; 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 ivy-leaved duckweed can survive?

Minimum survivable temperature is roughly below about −20 °C. Ivy-leaved Duckweed is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is ivy-leaved duckweed?

Ivy-leaved Duckweed is rated USDA 4-10 and RHS H7 — Hardy in the severest European continental winters.

Can ivy-leaved duckweed survive winter outside?

Plant it out within USDA 4-10 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 ivy-leaved duckweed below its minimum temperature?

It tolerates winter lows to about −20 °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.