Cold hardiness & minimum temperature

Is Canary Reed Grass (Phalaris arundinacea)cold hardy? Hardiness zone & min temp

Also called Reed Canary Grass, Ribbon Grass, Gardener's Garters.

More about canary reed grass

About Canary Reed Grass

Phalaris arundinacea · also called Reed Canary Grass, Ribbon Grass · flowering

Canary Reed Grass is a vigorous, rhizomatous wetland grass with broad, strappy leaves that can be variegated in cultivated forms (Phalaris arundinacea var. picta 'Gardener's Garters'). It thrives at pond margins and in wet soils but spreads aggressively by creeping rhizomes, making containment essential in garden settings. Listed as a noxious weed in some US states. Generally considered low toxicity but may cause mild issues in livestock.

Cold limit: USDA 3-9 · RHS H7 (-30 to 35°C)

What canary reed grass's hardiness rating actually means

Yes — canary reed grass is genuinely cold hardy. Rated RHS H7 and USDA 3-9, 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 3-9 — 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. Canary Reed Grass is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for canary reed grass 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 canary reed grass go outside or overwinter — and where?

Plant it out within USDA 3-9 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 canary reed grass can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Canary Reed Grass hardiness — frequently asked questions

Is canary reed grass cold hardy?

Yes — canary reed grass is genuinely cold hardy. Rated RHS H7 and USDA 3-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Canary Reed Grass is hardy across USDA 3-9; 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 canary reed grass can survive?

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

What hardiness zone is canary reed grass?

Canary Reed Grass is rated USDA 3-9 and RHS H7 — Hardy in the severest European continental winters.

Can canary reed grass survive winter outside?

Plant it out within USDA 3-9 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 canary reed grass 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.