Cold hardiness & minimum temperature

Is Chinese Yam (Dioscorea polystachya)cold hardy? Hardiness zone & min temp

Also called Chinese yam, nagaimo, cinnamon vine, air potato.

More about chinese yam

About Chinese Yam

Dioscorea polystachya · also called Chinese yam, nagaimo · edible

Chinese yam is a hardy twining vine grown for its long, mucilaginous edible tuber (nagaimo) and the small aerial bulbils along its stems. Vigorous and cold-tolerant, it climbs readily and spreads aggressively, becoming invasive in some regions. The deep, brittle tuber takes a full season to size up and is eaten grated raw or cooked across East Asian cuisine.

Cold limit: USDA 4-9 (tuber overwinters in ground) · RHS H5 (15-28°C)

What chinese yam's hardiness rating actually means

Yes — chinese yam is genuinely cold hardy. Rated RHS H5 and USDA 4-9 (tuber overwinters in ground), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 4-9 (tuber overwinters in ground) — 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 −15 to −10 °C. Chinese Yam is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for chinese yam as it gets too cold:

It tolerates winter lows to about −15 to −10 °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 chinese yam go outside or overwinter — and where?

Plant it out within USDA 4-9 (tuber overwinters in ground) 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 chinese yam can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Chinese Yam hardiness — frequently asked questions

Is chinese yam cold hardy?

Yes — chinese yam is genuinely cold hardy. Rated RHS H5 and USDA 4-9 (tuber overwinters in ground), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Chinese Yam is hardy across USDA 4-9 (tuber overwinters in ground); 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 chinese yam can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Chinese Yam is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is chinese yam?

Chinese Yam is rated USDA 4-9 (tuber overwinters in ground) and RHS H5 — Hardy in most of the UK and in cold winters.

Can chinese yam survive winter outside?

Plant it out within USDA 4-9 (tuber overwinters in ground) 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 chinese yam below its minimum temperature?

It tolerates winter lows to about −15 to −10 °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.