Corylus colurna aka Turkish Filbert

Corylus colurna is known as Turkish hazel or Turkish filbert. This deciduous tree belongs to the birch family, Betulaceae. Its native range spans southeastern Europe, western Asia, and northern Iran. Garden trees reach 40–50 feet (12.2–15.2 metres) in height. Some reach 80 feet (24.4 metres), chiefly in their native range. Reported crown widths range from 20–50 feet (6.1–15.2 metres). Young trees form a neat pyramid with a balanced crown.

The trunk is stout, with dense branches that spread sideways. Trees grown in open space develop a broad crown. Thick, corky bark shows patches of brown and gray. Flakes peel away to expose orange-brown bark beneath. Young shoots have hairs and may follow a zigzag course. The simple leaves grow in an alternate pattern along stems. They are broad, green, and edged with two sizes of teeth. Hairs line the veins on the leaf undersides. Fall leaves turn yellow, though some show purple-red tones. Leaves can stay on the tree late in the season.

Flowers open in February or March, before the spring leaves. Each tree bears both male and female flowers. Yellow male catkins hang from branches in small groups. The tiny female flowers show little more than red tips. Nuts ripen in September and October, within hairy, spiny husks. Each cluster holds three to six nuts with hard shells. People can eat the seeds raw, cooked, or roasted. The seeds also yield an edible oil. Squirrels and other small mammals eat the nuts. PFAF lists no known hazards for this species.

Give this tree full sun for its best growth. It also accepts some shade and several soil types. Moist soil with good drainage suits new trees. Avoid heavy clay unless the soil has been improved. Established trees withstand drought, compacted ground, and city conditions. It grows slowly, though one source reports a medium pace. Sources list USDA zones 4–7 and the UK rating H6. Moving or planting trees can be difficult, with poor survival.

Turkish hazel serves as a lawn, shade, or street tree. Its bare branch pattern also gives winter interest. Fallen nuts can make a mess on paved ground. Serious pest and disease problems are uncommon, but damage can occur. Japanese beetles may strip leaves from parts of the crown. Aphids, caterpillars, gall mites, and sawflies may also attack. Possible diseases include honey fungus, silver leaf, and powdery mildew.