The black poplar (Populus nigra) is a tree belonging to the Salicaceae family. It is widely distributed in our country, both in the wild and cultivated, especially as an ornamental plant in some particular varieties. Its widespread presence justifies the regional dialect names by which it is known, such as “arbare” and “pibula” in Liguria, “pobbia nera” and “alnia” in Lombardy, “talpon negro” in Veneto, “b’dolla” and “fiopa” in Emilia, “populo nero” and “oppio da pali” in Tuscany, “bidolla” in Marche, “albuccio” in Lazio, “chioppe” in Abruzzo, “cuduli bianchi” in Campania, “zizuigo” in Puglia, “chiupparella” in Basilicata, “aggiocu” and “candelise” in Calabria, “arvanu” and “arbaneddu niuru” in Sicily, “fustialvu nieddu” and “linarbu” in Sardinia.
One thing not everyone knows is that the bark and buds of this tree have beneficial and healing properties, still used in herbal medicine today. Let’s get to know this plant better.
Black Poplar Description
The black poplar is a deciduous tree that can reach up to 30 meters in height, with a trunk diameter of up to 1 meter. It is not considered a long-lived tree, typically living for 80-100 years, although there are specimens over 130 years old with a robust trunk.
The trunk has an upright and straight posture, although large protuberances that deform its linear course are sometimes observed. The canopy is wide and densely branched, wide at the base and narrower at the top. The branches are cylindrical, not perfectly straight. Young branches have a greenish color, while they become darker and tend towards reddish as they mature.
Bark and Buds
The bark and buds are the parts of the black poplar that contain valuable active principles and healing properties. The bark is ashy in color in mature trees, while it is lighter and tending towards whitish in young plants. Initially, it is smooth, but over time, it cracks and appears longitudinally fissured. The buds are small, oblong-flattened in shape, covered with brown bracts, glabrous, and sticky.
The leaves of the black poplar are alternate on the branches and have a long, slightly compressed petiole on the upper sides. The shape varies from triangular to rhomboid, the base narrows abruptly to a wedge or is sometimes rounded, and the apex is pointed. The margin is serrated, with forward-pointing teeth. The surface is smooth and glabrous, with the upper side glossy green, while the lower side is paler.
Populus nigra is a dioecious plant, carrying male and female flowers on different plants, grouped in catkins. The male flowers are very dense and have numerous stamens, with anthers initially reddish and then dark purple until the pollen falls. Female flowers are more sparse, long and pendulous, with the ovary surrounded at the base by a kind of saucer-shaped calyx, and they are greenish-yellow in color. The flowers appear on the branches before the leaves, with abundant flowering occurring between March and April.
Fruits and Seeds
The fruit of the black poplar is a capsule that opens in two parts at full maturity, releasing numerous seeds. These seeds are equipped with a long, cottony white hair (pappus) that promotes wind dispersal.
Cultivation of Black Poplar
Black poplar is one of the most important trees in Italy, as its rapid growth makes it one of the flagship species of arboriculture for wood production. However, its economic importance has somewhat diminished in recent times. Due to its greater hardiness and intrinsic wood quality, the cultivation of white poplar (Populus alba) is preferred for industrial purposes. For ornamental use, the cultivar known as the cipressino (P. nigra var. italica or pyramidalis) is widespread. It is a cultivar derived directly from the black poplar and is also called pioppo lombrado. The cipressino is perfect for creating roadside tree lines, as it has a perfectly straight trunk and a columnar growth habit.
In Italy, the black poplar is native to all regions, although it is more prevalent in the northern regions. It grows from sea level up to 1,400 meters in altitude, rarely found in pure forests but more frequently in typical associations with willows.
It prefers areas with moist soil, often found near rivers and lakes where the soil is cool and deep. It thrives in clayey soils and can even withstand brief flooding. Due to these characteristics, its cultivation is also practiced to reinforce riverbanks. It can also grow in sandier or gravelly soils, but its root system must reach the water table.
Propagation of Black Poplar by Cuttings
To cultivate a black poplar, you can purchase a potted plant from a nursery or propagate it from a moderately young tree through cuttings. Cuttings of *Populus nigra* are done in winter, immediately after the leaves have fallen, by taking apical portions of lateral branches, approximately 30 cm in length. The cuttings should be placed, almost in their entirety, in damp sand, left outdoors throughout the winter in a semi-shaded area. By late spring, they will have developed roots and can be transplanted into a sufficiently large container.
It is advisable to keep the small tree in a pot until the following autumn when it can be planted in open ground. In spring and summer, it will be easier to control irrigation, which should be regular for young plants. Autumn transplanting allows the plant to establish itself adequately before the vegetative growth resumes. The soil where the black poplar will be planted should be deeply tilled and preferably well-fertilized with mature manure.
The planting distance depends on the purpose of cultivation and the selected cultivar. A black poplar in the garden needs at least 10 meters to develop its dense canopy and provide shade. Wood plantations are denser since the goal is not to shade a green space but to achieve rapid trunk growth. A hedge of *cipressino* can be created by planting at 2-3 meters apart in regular rows.
Pruning of Black Poplar
Ornamental poplars should be cared for rather than pruned, following their natural growth habit and trying to maintain the canopy in order by removing old branches damaged by the weather. Black poplars do not tolerate topping, although it is often done without a plan. A topped poplar resprouts abundantly and in a disorderly manner from the cutting point, but it is also more susceptible to wood cankers and other fungal diseases like rust.
In addition to rust, black poplars, especially mature specimens, are often subject to **armillaria mellea**, a fungus that lives at the expense of tree roots. A black poplar affected by this disease can be hazardous because the root system damaged by the fungus may give way under the weight of the tree itself.
Uses of Black Poplar Wood
Black poplar wood is soft in texture, whitish in color, very light, elastic, and porous. In the wood industry, it is mainly used for cellulose pulp production, plywood, particleboard panels, low-quality musical instruments, and lightweight packaging (such as sticks and matches). Additionally, it is a suitable species for biomass production due to its rapid growth.
Harvesting Black Poplar Bark and Buds
Black poplar buds are collected in early spring before they open. They should be dried in the shade in a well-ventilated area and stored in glass containers for best preservation. For bark, spring is also a good time for harvesting. Use a sharp knife to cut it into pieces of 10-15 cm, dry it in the sun, and store it in paper bags for long-term storage.
Properties and Herbal Uses
The most important active principles contained in the buds and bark of black poplar are tannins, resins, essential oil (populin), and the salipopusolide heteroside. The properties of the buds are astringent, anti-inflammatory, balsamic, and depurative. On the other hand, the bark has febrifugal properties. Additionally, they are part of a product called unguento populeo, useful as a sedative for hemorrhoid-related discomforts. For external use, black poplar buds are useful in treating burns, bruises, and minor skin abrasions. For internal use, they are used as a balsamic and antitussive remedy for bronchial conditions. In a domestic context, you can prepare a decoction with 2 g of buds in 100 ml of water, to be consumed in 2-3 cups a day. The bark reduces temperature during febrile states, and a decoction can be prepared with 2 g of dried substance in 100 ml of water.