PL. —Corylus colurnaBotanical illustration — drop image

Turkish Hazel

WinterSpringSummerFall

4a–7bHardiness zone

Background

Turkish hazel is a large deciduous tree native to southeastern Europe and western Asia. It forms a broadly pyramidal crown and develops corky, deeply ridged bark with age — an ornamental feature that persists through winter. Unlike most Corylus species, it grows as a non-suckering single-trunked tree, making it practical for formal landscapes, street-tree plantings, and specimen use.

It adapts to a wide range of soil types, including slightly alkaline conditions, and becomes drought-tolerant once established. Male catkins open in late winter before leaf emergence. The small edible nuts are enclosed in deeply lacinated, fringed husks, a distinctive feature within the genus. Turkish hazel is widely used as rootstock for grafting Corylus avellana cultivars because its strong root system and single-trunk form benefit graft stability. It shows high resistance to Eastern Filbert Blight, the most damaging hazelnut disease in North America, making it a reliable long-term planting where C. avellana fails.

The nuts are edible and nutritionally comparable to common hazelnut, though smaller. They attract squirrels, jays, and other wildlife throughout autumn, giving the tree consistent wildlife value alongside its structural ornamental qualities.

Good companions

Purple Coneflower Goldenrod Serviceberry Ninebark

Care guide

SunFull sun to part shade

WaterLow

SoilWell-drained, adaptable

Spacing20–30 ft

Height40–70 ft

Zone4a – 7b

Frost hardy

Seasonal tasks

winter

cutIn late winter while fully dormant, remove crossing or competing leaders to maintain a single central trunk. Cut cleanly at the branch collar; avoid flush cuts.

spring

sowApply a 3–4 in layer of mulch extending to the drip line, kept 3 in back from the trunk, to conserve moisture and moderate soil temperature during establishment.

sowPlant bare-root or container-grown tree in early spring after the ground thaws. Dig a hole twice the width of the root ball and no deeper than root depth. Water in thoroughly.

summer

sowWater deeply once per week during the first two full growing seasons. Reduce frequency in year three as the root system extends.

watchInspect foliage in midsummer for white powdery coating indicating powdery mildew. Improve air circulation by selective branch removal; apply sulfur-based fungicide if coverage is severe.

watchCheck leaves during wet summer periods for brown irregular fungal leaf spots. Rake and dispose of fallen leaves in autumn to reduce overwintering spore loads.

fall

cutHarvest nuts in early fall once husks begin to brown and nuts drop naturally. Spread on mesh screens for one to two weeks to dry before storing in a cool, dry location.

Common problems

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.

Fungal leaf spot

Symptoms

Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.

Treatment

Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.

Armillaria Root Rot

Symptoms

Thinning, yellowing canopy with progressive dieback; white, fan-shaped mycelial mats visible beneath bark at or just below the soil line; honey-colored mushroom clusters appearing at the trunk base or on surface roots in autumn.

Treatment

No chemical cure exists. Improve drainage and avoid any injury to roots or trunk. Remove severely infected trees along with as much root material as possible. Do not replant susceptible species in the same spot.