Japanese chestnut

Photo: KENPEI — CC BY-SA 3.0 · source

Survives zone 5 through 8

Harvest calendar

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

A comparatively small, early-bearing chestnut from Japan and Korea that can produce nuts while still under 4 m tall — prized in breeding programs for its resistance to both chestnut blight and Phytophthora ink disease, though the nuts themselves are often coarser and more variable in quality than sweet chestnut.

Hardiness

Zone 5–8

Habit

Tree

Edible part

Nut

Ripens

Sept–Oct

Mature size

Tree 10–15 m — not containerable

Light

Full sun

Soil pH

Castanea 4.5–6.5 — ⚠ LIME-INTOLERANT (calcifuge, unlike other nut trees). Quercus/Fagus 5.0–6.5

Environment

Temperate

Native range

Japan (Hokkaido, Honshu, Kyushu, Shikoku) and Korea — and long, widely cultivated in eastern China and Taiwan, though the sources describe orchards rather than established wild populations there.

Status

Cultivated

Years to fruit

3–5 yrs grafted

Growth speed

Medium growth rate — precocious, often fruiting while still only 3-3.5 m tall.

Spacing

900 cm (354 in) apart — about 81 m² (872 sq ft) per plant

Leaf shape

Oblong-lanceolate, 8-19 cm long by 3-5 cm wide, with a broadly cuneate or rounded base, an acuminate tip, and a finely serrate margin of small bristle-tipped teeth; the underside is tomentose with yellowish-brown scaly glands.

Root system

A strong taproot when young giving way to deep, wide-spreading laterals — chestnuts anchor well and stand drought once established, but they transplant badly for the same reason. Move them small, and never into wet ground: the tree is acutely susceptible to Phytophthora ink disease on soils that lie cold and saturated.

Fruit description

Spiny cupules hold 3-7 brownish nuts that are large but variable in size and often coarse or bland compared with sweet chestnut — an astringency that boiling in salted water removes.

Propagation

Grown from seed sown as soon as ripe — viability is short and seed must be kept moist (refrigerate in damp sand if storage is needed) — germinating in late winter or early spring; seedlings are usually left in nursery beds for 1-2 years before transplanting. Selected cultivars are propagated by grafting onto seedling rootstock.

Pollination

⚠ SELF-INCOMPATIBLE — needs TWO trees; a lone tree bears little or nothing

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.