Cold hardiness & minimum temperature

Is Porcupine Grass (Miscanthus sinensis 'Strictus')cold hardy? Hardiness zone & min temp

Also called Porcupine grass, Banded miscanthus, Striped eulalia.

More about porcupine grass

About Porcupine Grass

Miscanthus sinensis 'Strictus' · also called Porcupine grass, Banded miscanthus · flowering

Miscanthus sinensis 'Strictus' is a bold, stiffly upright ornamental grass cultivar of the Chinese silver grass species, prized for its distinctive horizontal yellow-cream banding across the arching green leaf blades — a feature unique among upright miscanthus forms. In mid to late autumn it produces airy, pinkish-copper plume panicles that age to silvery-white and persist attractively through winter. The critical care point is full sun — without sufficient light, the characteristic yellow banding fades to plain green. It holds the RHS Award of Garden Merit. Miscanthus grasses are not listed as toxic by the ASPCA, but classified as mildly-toxic due to the potential for mechanical injury from sharp leaf edges and limited specific pet-safety data.

Cold limit: USDA 5-9 · RHS H6 (-20 to 35°C)

What porcupine grass's hardiness rating actually means

Yes — porcupine grass is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. On the US scale that maps to USDA 5-9 — 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 about −20 to −15 °C. Porcupine Grass is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for porcupine grass as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 porcupine grass go outside or overwinter — and where?

Plant it out within USDA 5-9 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 porcupine grass can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Porcupine Grass hardiness — frequently asked questions

Is porcupine grass cold hardy?

Yes — porcupine grass is genuinely cold hardy. Rated RHS H6 and USDA 5-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Porcupine Grass is hardy across USDA 5-9; 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 porcupine grass can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Porcupine Grass is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is porcupine grass?

Porcupine Grass is rated USDA 5-9 and RHS H6 — Hardy throughout the UK and northern Europe.

Can porcupine grass survive winter outside?

Plant it out within USDA 5-9 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 porcupine grass below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.