Corylus colurna
Corylus colurna, the Turkish hazel, is a deciduous tree native to Eurasia.
Distribution and habitat
It is native to southeast Europe and southwest Asia, from the Balkans through northern Turkey to northern Iran.Description
It is a large species of hazel, reaching tall, exceptionally to tall, with a stout trunk up to in diameter, rarely to. The crown is slender and conical in young trees, becoming broader and irregular with age. The bark is pale grey-buff, with a thick, corky texture. On young trees, the main limbs are quite small in diameter in relationship to the straight trunk, and arise at almost a 90-degree angle. This makes the tree suitable for urban conditions and helps maintain a symmetrical crown which is popular with landscape architects.The leaves are deciduous, rounded, long and across, softly hairy on both surfaces, and with a coarsely double-serrate to shallowly lobed margin. The buds are ovoid, pale brown. The flowers are produced in late winter or early spring before the leaves; the species is monoecious, with the individual catkins single-sex, but both sexes on the same tree ; the male catkins are conspicuous, pale yellow and 5–10 cm long, the female very small and inconspicuous, largely concealed in the buds, with only the bright red 1–3 mm long styles visible.
The fruit is a nut and may be known as the Turkish hazel nut, Turkish nut, or Constantinople nut. It is about 1–2 cm long, surrounded by a thick, softly spiny and bristly involucre 3 cm diameter, which encloses all but the tip of the nut; the nuts are borne in tight clusters of 3–8 together, with the involucres fused at the base. The fruit matures in September to October and is edible. Its taste is very similar to common hazel, but it is smaller and has a thicker nut shell. They are occasionally gathered from the wild as well as from urban trees, but their small size and very hard, thick nut shell makes them of little or no commercial value. Corylus colurna is however important in commercial hazelnut orchards, as it does not sucker, making it the ideal rootstock on which to graft the nut-bearing common hazel cultivars. Nut production is irregular and occurs every two to three years
Root
Corylus colurna has fibrous roots. The roots are not adventitious, meaning they do not form suckers. This makes C. colurna desirable for grafting on the rootstock over a single stemmed trees. This allows it to be grown in poorer and rocky soils.Cultivation
Corylus colurna has a medium growth rate. It is occasionally drought tolerant and alkaline soil tolerant. However, it prefers moist, well-drained soil, as well as full sun. Once established C. colurna is tolerant of heat, cold, and drought.There are no serious pests or problems with C. colurna.
Corylus colurna is not easily transplantable and will need extra watering in summer after transplanting. It will take about two years after transplant for the tree to become established and survive on its own.
Corylus colurna has received the Royal Horticultural Society's Award of Garden Merit.