Cold hardiness & minimum temperature

Is Field Horsetail (Equisetum arvense)cold hardy? Hardiness zone & min temp

Also called Field Horsetail, Common Horsetail, Bottlebrush Plant.

More about field horsetail

About Field Horsetail

Equisetum arvense · also called Field Horsetail, Common Horsetail · herb

Field Horsetail is a prehistoric vascular plant with deep-creeping rhizomes, producing two distinct stem types: fertile spore-bearing stems in early spring and lush, whorled green vegetative stems in summer. Rich in silica and used in traditional herbal medicine as a diuretic and for connective tissue support. Extremely persistent — considered a troublesome weed in gardens but valuable in herbal use.

Cold limit: USDA 3-11 · RHS H7 (-30–35°C)

What field horsetail's hardiness rating actually means

Yes — field horsetail is genuinely cold hardy. Rated RHS H7 and USDA 3-11, 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 3-11 — 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 below about −20 °C. Field Horsetail is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for field horsetail 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 horsetail go outside or overwinter — and where?

Plant it out within USDA 3-11 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 field horsetail can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Field Horsetail hardiness — frequently asked questions

Is field horsetail cold hardy?

Yes — field horsetail is genuinely cold hardy. Rated RHS H7 and USDA 3-11, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Field Horsetail is hardy across USDA 3-11; 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 field horsetail can survive?

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

What hardiness zone is field horsetail?

Field Horsetail is rated USDA 3-11 and RHS H7 — Hardy in the severest European continental winters.

Can field horsetail survive winter outside?

Plant it out within USDA 3-11 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 field horsetail 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.