Cold hardiness & minimum temperature

Is Spreading Spike Moss (Selaginella kraussiana)cold hardy? Hardiness zone & min temp

Also called Krauss's Spike Moss, Mat Spikemoss, Trailing Spike Moss.

More about spreading spike moss

About Spreading Spike Moss

Selaginella kraussiana · also called Krauss's Spike Moss, Mat Spikemoss · houseplant

Spreading Spike Moss is a fast-growing, mat-forming spike moss native to the Azores, Canary Islands, and parts of Africa, widely naturalised in many warm-temperate regions. Its bright emerald-green, moss-like foliage spreads readily across moist soil. Ideal for terrariums and humid shelves. Not toxic to cats and dogs.

Cold limit: USDA 6-10 · RHS H4 (10-24°C)

What spreading spike moss's hardiness rating actually means

Yes — spreading spike moss is genuinely cold hardy. Rated RHS H4 and USDA 6-10, 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 — 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. Spreading Spike Moss is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for spreading spike moss 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 spreading spike moss 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 spreading spike moss can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

Spreading Spike Moss hardiness — frequently asked questions

Is spreading spike moss cold hardy?

Yes — spreading spike moss is genuinely cold hardy. Rated RHS H4 and USDA 6-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Spreading Spike Moss 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 spreading spike moss can survive?

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

What hardiness zone is spreading spike moss?

Spreading Spike Moss is rated USDA 6-10 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can spreading spike moss 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 spreading spike moss 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.