hardy kiwi / kiwiberry

Photo: Björn Appel — CC BY-SA 3.0 · source

Survives zone 4 through 8

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Kiwiberry — sweet, aromatic, grape-sized, eaten whole skin and all. The most cold-hardy commercially relevant kiwi (to roughly zone 4), which is also why it readily escapes cultivation in parts of the US Northeast — see spread warning. Fruit color ranges from green to greenish-yellow through to a form with fully purple-red skin, colouring best in full sun — this purple form circulates in the trade as "Actinidia purpurea" or "A. arguta var. purpurea," but POWO treats it as a synonym of this species, not a distinct taxon.

Spread warning. Classified a Tier 2 invasive species by New York State DEC and documented as naturalized/spreading in Connecticut, Vermont, Massachusetts, New York and New Jersey, forming dense canopy-smothering stands — traces to 1870s–1900s ornamental plantings. Site and prune with that in mind, especially in the US Northeast.

Hardiness

Zone 4–8

Habit

Vine

Edible part

Fruit

Ripens

Sept–Oct

Mature size

Very vigorous vine 8–10 m, to 15 m and more unpruned — a mature plant can carry 100 kg of fruit, so the trellis has to be substantial

Light

Full sun; tolerates partial — fruits best in sun

Soil pH

5.0–6.5 (slightly acid)

Environment

Temperate forest

Native range

China (22–47°N, from the Chang-Bai Mountains to Yunnan's Dawei Mountains), Japan, Korea, Taiwan, Russian Far East (Primorye, Sakhalin), Kuril Islands, Manchuria

Status

Cultivated

Years to fruit

3–5 yrs from a grafted vine ('Issai' from yr 2–3)

Growth speed

Vigorous — can put on up to about 9 m of new growth in a single season once established.

Spacing

305 cm (120 in) apart — about 9.3 m² (100 sq ft) per plant

Leaf shape

Broad-ovate to elliptic, dark green, to about 12–13 cm, finely serrated margins, hairless on both surfaces.

Root system

A heart-root pattern — several primary roots radiating down and out from the crown; roots burn easily from fertilizer placed too close, and the plant is susceptible to root-knot nematodes and Phytophthora root rot.

Fruit description

Grape-sized berries (2–3 cm), smooth edible skin without fuzz, green to greenish-yellow sometimes with a purple-red blush; green flesh, sweeter and less acidic than fuzzy kiwifruit, with small easily-eaten seeds.

Propagation

Softwood cuttings (spring) root more readily than hardwood; commercial growers graft named cultivars onto seedling rootstock.

Pollination

DIOECIOUS — needs male and female plants

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.