Cold hardiness & minimum temperature

Is So Jujube (Ziziphus jujuba 'So')cold hardy? Hardiness zone & min temp

Also called So jujube, contorted jujube.

More about so jujube

About So Jujube

Ziziphus jujuba 'So' · also called So jujube, contorted jujube · edible

'So' is a distinctive jujube cultivar with strongly contorted, zigzagging branches that give striking winter structure, plus small, sweet, date-like fruit. A compact, heat- and drought-tolerant deciduous tree, it doubles as an ornamental and a cropper. Like other jujubes it thrives in poor, alkaline, free-draining soil and hot summers, fruiting best with a pollinator nearby.

Cold limit: USDA 6-9 · RHS H4 (-20 to 40C (growing optimum 25-38C))

What so jujube's hardiness rating actually means

Yes — so jujube is genuinely cold hardy. Rated RHS H4 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H4 means: Hardy in an average winter across much of the temperate world. On the US scale that maps to USDA 6-9 — 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 −10 to −5 °C. So Jujube is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for so jujube as it gets too cold:

It tolerates winter lows to about −10 to −5 °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 so jujube go outside or overwinter — and where?

Plant it out within USDA 6-9 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 so jujube can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H4 figure above.

So Jujube hardiness — frequently asked questions

Is so jujube cold hardy?

Yes — so jujube is genuinely cold hardy. Rated RHS H4 and USDA 6-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. So Jujube is hardy across USDA 6-9; 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 so jujube can survive?

Minimum survivable temperature is roughly about −10 to −5 °C. So Jujube is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is so jujube?

So Jujube is rated USDA 6-9 and RHS H4 — Hardy in an average winter across much of the temperate world.

Can so jujube survive winter outside?

Plant it out within USDA 6-9 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 so jujube below its minimum temperature?

It tolerates winter lows to about −10 to −5 °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.