Grey willow, a tree associated with myths and legends


On the banks of Portugal’s rivers and streams stands an elegant and mysterious figure – the grey willow (Salix atrocinerea). This tree, also known as grey sallow, stands out for its striking presence, in which the dark trunk contrasts with its two-tone branches and leaves, thus creating an unusual atmosphere. Meet this remarkable species.

The grey willow is a shrub or small tree native to Atlantic Europe and the Mediterranean region, adapted to moist soils and which can be found at the edge of watercourses. Its presence along the banks of Portuguese rivers helps the landscape and provides a vital habitat for several life forms.

The grey willow (Salix atrocinerea) is a deciduous tree and rarely exceeds twelve meters in height. Its treetop is not very dense and the bark of the trunk, which is grey and smooth in the beginning, takes on over time a brownish hue, sometimes very black. The leaves, elongated in shape, and largely lanceolate, resemble the tip of a spear, with wider ends. And whereas the upper part of the leaf, facing the light, displays a dark-green colour, the lower part is whitish due to the presence of reddish long white hairs.

The grey willow’s magic is clearly there  during flowering. It stands out for its early flowering, between January and March. This natural show turns the seemingly simple branches of the tree, which at this point are leafless, into authentic works of art, covered by small flowers of greenish, white or yellowish tones, which contrast with the dark trunk. It is a dioecious flowering species (that is, male plants have only male flowers and female plants have only female flowers), arranged in vertical, cluster-like bunches.

But the apparent simplicity of these flowers hides an intrinsic complexity: by attracting pollinators such as bees and butterflies, which benefit from the nectar of these flowers, a symbiosis between the grey willow and these pollinators is created, thus assisting biodiversity. The fruit of the less showy grey willow is a hairy capsule, also covered with hair opening up in two halves (called valves), which matures between April and May. These seeds are dispersed by wind or water, in small flakes that resemble cotton, in a process very similar to that of poplars, also from the salicaceae family.

Despite its modest size, this tree is surprisingly versatile as regards its applications. It tolerates land submerged by winter floods and is used in the stabilization of lands and the fight against erosion, due to both its long and deep root system, which makes it a frequent choice. It plays also a crucial role in natural engineering, assisting the recovery and stabilization of river banks and acting as an effective barrier against the wind.

Its use in the process of treating polluted water is currently being studied, testing its effectiveness in turning harmful substances into organic matter, thus granting it a promising role in environmental de-pollution.

In addition to its ecological relevance, the grey willow is also acknowledged for containing salicin, a substance extracted from the bark, from which we obtain salicylic acid, which is the base of acetylsalicylic acid, an essential compound of Aspirin, used in the treatment of fever, headaches, among other conditions. Its properties were already recognized by the Egyptians and Sumerians, but it was only marketed as medicine in 1899 by Bayer and became famous worldwide after that.

Did you know that…

The genus Salix includes around 450 species, mostly shrubs. In Portuguese territory, this is one of the main elements of riverine flora, not only because it can be found nearly everywhere in these ecosystems but also given the vast array of species.

In Roman mythology, the willow tree had a prominent role and was consecrated to the goddess Juno, and was a symbol of values such as unity, fidelity and the protection of women. The species was believed to have the ability to stop bleeding and prevent abortions and played therefore an important role in the beliefs and rituals of that time.

In China, the willow tree plays a vital role in protecting agricultural land and is planted strategically to act as a barrier against desert winds, thus playing a crucial role in preserving crops. It is also considered a symbol of immortality in Chinese tradition.

Given its ability to hybridize with other species of the genus Salix, continuous genetic and molecular studies are necessary to identify it.

  • Grey willow

    Salix atrocinerea

  • Plant

  • Genus


  • Family


  • Common names

    Sallow, grey sallow, ashtray, willow, grey Willow, black willow, grey rattan

  • Origin

    Atlantic Europe and Western Mediterranean Region.

  • Habitat

    Wet and flooded places, particularly along the banks of rivers and streams

  • Distribution

    Atlantic Europe and Western Mediterranean Region. In Portugal, it can be found all over the national territory

  • Conservation Status

    Least Concern (LC) according to IUCN

  • Size

    Up to 10 meters

  • Longevity

    Up to 50 years

How to tend to this species?

The grey willow occurs naturally on the banks of watercourses, in permanently moist or even soggy soils.

In the forests under The Navigator Company management, this species can be found in the floristic composition of watercourses from the North to the South of the country, often as a typical specie of the natural habitats referred to in the Willow Tree Habitats Directive (type 92A0) and present in riparian Alder Groves (subtype 91E0pt1).

In 2017, several grey willows were also planted along the waterline that flows through  Quinta de São Francisco. In this process of ecological renovation, there was room to accommodate the planting of other native species typical of riparian lines, such as alder, narrow-leaved ash or elderberry, just to name a few.

With limited circulation, nature follows its course and simple maintenance actions are carried out when necessary for the proper functioning of the habitat and its natural regeneration, along with  assessment of the conservation status of habitats or control of invasive species, thus preserving biological wealth.