Cold hardiness & minimum temperature

Is Marsilea quadrifolia (Marsilea quadrifolia)cold hardy? Hardiness zone & min temp

Also called Four-Leaf Water Clover, European Water Clover.

More about marsilea quadrifolia

About Marsilea quadrifolia

Marsilea quadrifolia · also called Four-Leaf Water Clover, European Water Clover · houseplant

Marsilea quadrifolia is an aquatic fern that looks deceptively like a four-leaf clover, with long-stalked, four-lobed leaves that float on or stand just above shallow water. Spreading by creeping rhizomes, it forms a low carpet in ponds, bog gardens and aquariums. As a fern it reproduces by spores rather than flowers, and tolerates both submerged and emergent growth.

Cold limit: USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid) · RHS H4 (15-26°C)

What marsilea quadrifolia's hardiness rating actually means

Yes — marsilea quadrifolia is genuinely cold hardy. Rated RHS H4 and USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid) — 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 −10 to −5 °C. Marsilea quadrifolia is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for marsilea quadrifolia as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 marsilea quadrifolia go outside or overwinter — and where?

Plant it out within USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid) 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 marsilea quadrifolia can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Marsilea quadrifolia hardiness — frequently asked questions

Is marsilea quadrifolia cold hardy?

Yes — marsilea quadrifolia is genuinely cold hardy. Rated RHS H4 and USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Marsilea quadrifolia is hardy across USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid); 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 marsilea quadrifolia can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. Marsilea quadrifolia is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is marsilea quadrifolia?

Marsilea quadrifolia is rated USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid) and RHS H4 — Hardy in an average winter across much of the temperate world.

Can marsilea quadrifolia survive winter outside?

Plant it out within USDA 6-10 (hardy as a pond marginal where the rhizome does not freeze solid) 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 marsilea quadrifolia below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.