Cold hardiness & minimum temperature

Is Four-Leaf Water Clover (Marsilea mutica)cold hardy? Hardiness zone & min temp

Also called Australian Water Fern, Variegated Water Clover, Lucky Clover Aquatic Fern.

More about four-leaf water clover

About Four-Leaf Water Clover

Marsilea mutica · also called Australian Water Fern, Variegated Water Clover · tropical

Four-Leaf Water Clover is an aquatic fern native to Australia producing distinctive four-lobed floating leaves resembling a four-leaf clover, often with attractive banding. Suitable for pond edges, container water gardens, and aquariums. As a true fern, it is considered pet-safe — the ASPCA lists most true ferns as non-toxic to cats and dogs.

Cold limit: USDA 6-11 · RHS H4 (10-28°C)

What four-leaf water clover's hardiness rating actually means

Yes — four-leaf water clover is genuinely cold hardy. Rated RHS H4 and USDA 6-11, 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 6-11 — 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. Four-Leaf Water Clover is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for four-leaf water clover 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 four-leaf water clover go outside or overwinter — and where?

Plant it out within USDA 6-11 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 four-leaf water clover can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Four-Leaf Water Clover hardiness — frequently asked questions

Is four-leaf water clover cold hardy?

Yes — four-leaf water clover is genuinely cold hardy. Rated RHS H4 and USDA 6-11, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Four-Leaf Water Clover is hardy across USDA 6-11; 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 four-leaf water clover can survive?

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

What hardiness zone is four-leaf water clover?

Four-Leaf Water Clover is rated USDA 6-11 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can four-leaf water clover survive winter outside?

Plant it out within USDA 6-11 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 four-leaf water clover 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.