The Corylus colurna, or colurno, commonly called Nocciolo di Costantinopoli, is a medium-sized, deciduous tree, native to Asia, Mediterranean. It has an erect stem, with symmetrical branches, and a pyramidal crown, very regular, and can reach 12-15 meters in height; the bark is gray-brown, smooth in very young specimens, it tends to crack in a flashy way with the passing of the years, and also to break in flakes, showing the lower bark, of orange color. The leaves of the colurno are roundish, of dark green color, slightly wrinkled, with serrated margin, they become yellow in autumn, before falling; at the end of winter it produces elongated, yellowish, male inflorescences and roundish, yellow-green female inflorescences, with red stamens. In summer the Corylus colurna produces large walnuts, gathered in groups of four or five, wrapped in long paper bracts covered with soft thorns. These trees have very slow growth, and can remain below 5-6 meters for many years.
Speaking of which are the best tricks for the cultivation of the specimens of trees belonging to the Corylus colurna variety, it is possible to say that the colurno, or core of Constantinople, adapts to any exposure, preferring but the full sun. It does not fear the cold and can withstand temperatures well below zero. The corylus colurna is suitable for street trees because it tolerates pollution very well.
These trees are very rustic and resistant and are well suited to different environments, without showing any particular signs of suffering.
As for the supply of water to Corylus colurna plants, it is good to know that these trees are satisfied with the rains, they can withstand the drought without any problem, especially if they are long-lived specimens.
As regards, however, the younger specimens and newly planted, it is good to provide regular water supply, to allow them to develop better. Be careful to check that the soil dries before proceeding with a new watering and avoid the formation of water stagnations.
the corylus colurna they have the great advantage of developing in any terrain, even in the case of very poor and dry soils; they prefer well-drained, rich and deep substrates.
The hazel trees of Constantinople are resistant and can be grown with satisfaction in any type of soil, but stagnant water can cause the onset of fungal diseases and root rot.
The multiplication of the specimens belonging to this genus occurs by cuttings, using small portions of the young branches, which must be rooted in a mixture of sand and peat in equal parts; It is also possible to sow its fruits.
The new shoots and the new seedlings must be kept in the container for some time, in order to allow them to acquire the necessary strength and useful vigor to prevent them from being affected by the change, when they are placed in the ground.
Nocciolo di Costantinopoli, Colurno - Corylus colurna: Pests and diseases
In general it is possible to say that the trees that belong to this variety have a rustic and resistant character and are not affected by pests or diseases.