Hebei walnut

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.

Ma walnut is a narrow Chinese endemic of hybrid origin — molecular studies show it arose from crosses between English walnut and the Manchurian walnut — and its nuts are the classic 'wenwan' walnuts of Chinese folk tradition, hand-carried and worn smooth as meditation objects, with a well-matched pair of prized wild nuts reportedly selling for tens of thousands of dollars.

Hardiness

Zone 5–8

Habit

Tree

Edible part

Nut

Ripens

Sept–Oct

Mature size

Large tree — the height of this rare endemic is poorly documented and published figures conflict; both its parent species (J. regia and J. mandshurica) reach 25–30 m. Not containerable

Light

Full sun

Soil pH

6.0–7.5 (near-neutral; lime-tolerant)

Environment

Temperate

Native range

A narrow endemic of northern China, historically centered on the Taihang Mountains of northern Hebei Province and now known from scattered mountainous populations across Hebei and Shanxi and the Beijing and Tianjin municipalities.

Status

Both wild and cultivated

Years to fruit

5–10 yrs

Growth speed

Moderate

Spacing

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

Leaf shape

Pinnately compound leaves with 7–15 leaflets, most commonly 9–11, with glabrescent (nearly hairless) veins on the leaflet undersides — a trait inherited from its English walnut parentage rather than the hairier-veined J. mandshurica.

Root system

A deep, dominant taproot from the first season with strong laterals following later — the reason walnuts stand drought once settled and the reason they must be planted small and never moved. The roots also release juglone, which suppresses many other plants under the canopy; keep tomatoes, apples and most solanaceous crops well clear.

Fruit description

Nuts show morphology intermediate between its two parent species: roughly two ridges on the outer shell surface and an incomplete four-celled internal chamber at the base, positioned between the two-chambered nuts of section Cardiocaryon and the four-chambered nuts of section Juglans. Wild nuts are hard-shelled and less studied for culinary quality than common walnuts, but well-shaped, symmetrical pairs are highly prized as hand-held wenwan collectibles rather than primarily as a food crop.

Propagation

Grafting onto walnut seedling rootstock for the selected forms — and in this species the selection is often for the shell rather than the kernel, since exceptionally sculptured nuts are prized as Chinese handling pairs and can be worth far more than the food. Seed after cold stratification for rootstocks.

Pollination

Monoecious but HETERODICHOGAMOUS — a 2nd cultivar of the opposite type greatly improves set

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.