Populus nigra is a deciduous arboreal plant of impressive size native to Europe and western Asia, present in the wild also in the American continent. It has a round, domed, rather broad, but sparse crown, which rapidly reaches 30-35 meters in height, it is not uncommon to see specimens of black poplar columnar bearing; the leaves are alternate, dark green on the upper side and yellowish-green on the lower side, triangular or diamond-shaped, with the toothed margin. The bark is gray in the young specimens, it tends to darken with the age of the plant, furrowed by deep fissures. The male and female catkins grow on different trees, the female ones are white tufts and cottony seeds, the male ones are gray, brown or reddish. It tends to develop long superficial roots. In America we also find P. deltoides, and in Italy and in Europe also P. alba is widespread, with oval gray-green leaves. P. tremula, widespread in Europe, Africa and Asia, has roundish leaves that sway even in very mild winds.
The black poplar he prefers very bright, sunny positions, but he also adapts well to partial shade, he does not like the complete shadow. It does not fear the cold or even the wind, it is very resistant to pollution and is therefore very used for street trees.
It can also grow spontaneously along the banks of the ditches or in alluvial areas.
Soil and watering
The trees of populus nigra they prefer soils rich in organic matter, light and well drained, hardly adapt to inconsistent and sterile soils; in nature they prefer wetlands, near rivers and streams, since they do not tolerate long-term droughts. It is therefore advisable to periodically bury a good organic fertilizer at the foot of the plant, at least twice a year, it is also advisable to water the poplars if prolonged periods of drought occur.
As for the multiplication of plants of this variety, it usually occurs by cutting.
In the spring period the cuttings are rooted in a mixture of peat and sand in equal parts and the new plants are cultivated in a greenhouse for at least two years before being planted, since the young specimens can sometimes fear the cold and the wind.
Propagation can also take place by seed; in this case it is advisable to use several seeds since the poplar is not very high.
In autumn you can take basal suckers, which usually adult plants develop in large numbers, to be buried in a soft and rich in organic matter, to allow a better development.
Black poplar - Populus nigra: Pests and diseases
Often this kind of plants is attacked by the black poplar aphid, which completely spoils the buds.
The young plants of populus nigra they can undergo lethal attacks by the chrysomela, which devours their leaves. In addition, poplars can be attacked by oziorrinco and rodilegno, but in general the parasites are more concerned with young specimens, as the adult plants are more resistant to pest attacks.