Corylus chinensis Seeds | Chinese Hazel
LATIN NAME: Corylus chinensis
COMMON NAME: Chinese Hazel
Plant Profile
The husk is the diagnostic organ. In Chinese hazel the involucre wrapping the nut is bell-shaped and pinched in above the fruit, so the nut sits inside a bristly vest longer than the nut itself. The surface carries stiff stalked glands, which make the husk feel like a burr and separate it from the smooth leafy husks of the European hazel.
Corylus avellana, the European hazel, spreads into a multi-stemmed shrub with small nuts and a husk that flares open rather than closing above the fruit. Corylus colurna, the Turkish tree hazel, also makes a single trunk, but its husk is deeply fringed. Chinese hazel differs from both in the glandular, constricted husk and in the size of the nut inside it.
Male catkins form in autumn and hang through winter, lengthening as the weather warms until they shed pollen on the wind. Female flowers are almost invisible: a bud with two slender crimson stigmas pushed out to catch that pollen. The species is largely self-incompatible, controlled by a self-recognition locus, and strongly protandrous, so a lone tree is often a barren one and two different trees are the practical answer.
Nuts are ready when the husks yellow, begin to open and the shells have turned the colour of milky coffee. Collect them from the ground promptly, because squirrels and weevils work faster than any picker. Rub the husks off while they are still soft, spread the nuts in a single layer in an airy room, and store them cool and dry in a mouse-proof container.
Hazelnuts are eaten roasted, and the heat loosens the papery skin that clings to the kernel so it can be rubbed away in a cloth. Cold pressing gives a pale oil used in dressings and pastry, while kernels ground with sugar and cocoa become the base of praline. The tree earns its place in a park or a large garden, and coppiced wood has gone into walking sticks and charcoal.
Science & Biotechnology
Hazelnut oil is dominated by oleic acid, with linoleic acid and smaller amounts of palmitic and stearic acid, and the kernel carries enough tocopherol to keep the oil from turning rancid quickly. The kernel proteins matter to clinicians: the hazelnut allergens Cor a 1, a Bet v 1 relative, Cor a 8, a lipid transfer protein, Cor a 9, an 11S globulin, and Cor a 14, a 2S albumin, the last two being linked to severe reactions.
The shell is a hard lignified coat that shields the kernel from insects and from drying, and the husk around it is a tannin store, rich in proanthocyanidins and flavonoids such as taxifolin. Husks left after hulling were once steeped for dye and for leather work; today they are composted or burned as low-grade fuel.
Uses & Benefits
Most hazels are thickets. Corylus chinensis is a timber tree: a single grey trunk that lifts a rounded crown well above head height, carrying the largest hazel nuts in China. Anyone who knows hazels only as hedgerow shrubs is startled by the scale of it.
Chinese hazel grows in mixed mountain forest on deep soils in moist valleys and along streams, usually between 1,200 and 3,500 metres. It tolerates shade while young, persists in the understorey of oaks and pines, then pushes into a gap when one opens. Wild stands are scattered and the crop is gathered rather than managed; most nuts that reach a market come from trees nobody planted.
Growing from Seed
Hazel seed is a nut with a hard shell, so sow it in autumn, shell and all, in a deep pot of two parts loam, one part leaf mould and one part coarse grit, covering each nut by about twice its own depth. Push wire mesh over the pot, because mice find it first. Keep the pots in a shaded frame, and give a tree hazel five or six metres of room when it is finally planted out.
Trained as a standard, a Chinese hazel wants a clear trunk to about a metre and a half, with the lower shoots rubbed out while they are still soft. Cut out any suckers at the base and remove crossing branches in late winter before the catkins open. Young trees benefit from a stake and a mulch of leaf mould; older trees are fully hardy, though late frost can scorch the catkins and cost a crop without harming the tree.
Our Take
Hazels are easy to grow and hard to keep away from squirrels, so if you want a crop, plant more than you need. Corylus colurna is the other tree hazel, a Turkish species with a deeply fringed husk, and Corylus avellana is the European shrub that most commercial nuts come from. Add American hazelnut as a third partner; grown together, they pollinate one another better than any single tree manages alone.
Related Reading
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