Cold hardiness & minimum temperature

Is Issai Hardy Kiwi (Actinidia arguta 'Issai')cold hardy? Hardiness zone & min temp

Also called Issai Hardy Kiwi, Baby Kiwi, Kiwi Berry, Bower Vine.

More about issai hardy kiwi

About Issai Hardy Kiwi

Actinidia arguta 'Issai' · also called Issai Hardy Kiwi, Baby Kiwi · edible

Issai Hardy Kiwi is a self-fertile cultivar of Actinidia arguta producing grape-sized, smooth-skinned fruits eaten whole. It is one of the hardiest kiwis, tolerating temperatures to -25 °C. A vigorous deciduous vine, it thrives in full sun with consistent moisture and well-drained, fertile soil.

Cold limit: USDA 4–9 · RHS H7 (-25 to 35 °C)

What issai hardy kiwi's hardiness rating actually means

Yes — issai hardy kiwi is genuinely cold hardy. Rated RHS H7 and USDA 4–9, 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 4–9 — 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. Issai Hardy Kiwi is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for issai hardy kiwi 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 issai hardy kiwi go outside or overwinter — and where?

Plant it out within USDA 4–9 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 issai hardy kiwi can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

Issai Hardy Kiwi hardiness — frequently asked questions

Is issai hardy kiwi cold hardy?

Yes — issai hardy kiwi is genuinely cold hardy. Rated RHS H7 and USDA 4–9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Issai Hardy Kiwi is hardy across USDA 4–9; 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 issai hardy kiwi can survive?

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

What hardiness zone is issai hardy kiwi?

Issai Hardy Kiwi is rated USDA 4–9 and RHS H7 — Hardy in the severest European continental winters.

Can issai hardy kiwi survive winter outside?

Plant it out within USDA 4–9 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 issai hardy kiwi 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.