Cold hardiness & minimum temperature

Is Field Mouse-ear (Cerastium arvense)cold hardy? Hardiness zone & min temp

Also called Field Mouse-ear, Field Chickweed, Field Mouse-ear Chickweed.

More about field mouse-ear

About Field Mouse-ear

Cerastium arvense · also called Field Mouse-ear, Field Chickweed · flowering

Field mouse-ear is a low, mat-forming perennial native to grasslands, rocky outcrops, and dry banks across the UK, Europe, and North America, growing naturally in poor, well-drained soils in full sun. Its starry white five-petalled flowers appear prolifically from April to August, making it an attractive, drought-tolerant ground cover for sunny rock or gravel gardens. The single most important care fact is that it requires freely draining, lean soil and will rot quickly in heavy clay or moist conditions. Field mouse-ear is not listed on the ASPCA Toxic and Non-Toxic Plant database; it is classified here as mildly-toxic out of caution as no confirmed pet-safe clearance was found.

Cold limit: USDA 3-10 · RHS H7 (-40°C to 25°C)

Watch for — Crown rot in wet or clay soils: The most common problem; plants collapse and die in winter if drainage is inadequate. Always plant in gritty, free-draining soil or raised beds.

What field mouse-ear's hardiness rating actually means

Yes — field mouse-ear is genuinely cold hardy. Rated RHS H7 and USDA 3-10, 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 3-10 — 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. Field Mouse-ear is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for field mouse-ear 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 field mouse-ear go outside or overwinter — and where?

Plant it out within USDA 3-10 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 field mouse-ear can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Field Mouse-ear hardiness — frequently asked questions

Is field mouse-ear cold hardy?

Yes — field mouse-ear is genuinely cold hardy. Rated RHS H7 and USDA 3-10, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Field Mouse-ear is hardy across USDA 3-10; 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 field mouse-ear can survive?

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

What hardiness zone is field mouse-ear?

Field Mouse-ear is rated USDA 3-10 and RHS H7 — Hardy in the severest European continental winters.

Can field mouse-ear survive winter outside?

Plant it out within USDA 3-10 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 field mouse-ear 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.