Four Willow species are shown here – White, Grey, Weeping and Goat Willow. For information on the Crack Willow click HERE. Willows and Poplars are closely related but are easy to differentiate. Willow leaves are generally long and thin (apart from the Goat Willow) and have shorter and fatter catkins. Poplar leaves are triangular or diamond-shaped and catkins are long. For more information on Poplars click HERE
Willows are pollinated by insects (Poplars are wind pollinated). Willows have male flowers on one tree and female flowers on another tree. Technically they are called ‘dioecious’ from the Greek meaning ‘2 households’. The flowers are in the form of catkins. Female and male catkins look different. Male catkins have anthers that carry bright yellow pollen. At the base of each flower is a pot of nectar. Insects, usually early bees, collect the nectar (to make honey) and, as they do so, get coated in pollen, which they then transfer to the female flower when they go to its nectar pot. Female catkins are greener, stay on the tree longer and eventually release seeds.
Willow species easily form hybrids with other Willows. Some hybrids are natural and you may come across trees that have features of both parents. This makes identification very difficult even for experts.
The White Willow (Salix alba) is native to Europe (including Britain), Asia and north Africa. It is common along rivers and lowland valleys. It is a large, impressive tree. The leaves are narrow but shorter than those of the Crack Willow and have silvery-white hairs. The tree looks strikingly white in summer.
The Grey Willow (Salix cinerea), also known as the Grey Sallow, is native to western Europe including Britain. It grows naturally everywhere. It is a shrub and rarely a tree. It can be confused with the Goat Willow but it has longer leaves and large ‘stipules’ at the base of each leaf.
The Weeping Willow (Salix alba ‘Tristis’), also called the Golden Weeping Willow, is a hybrid cultivated variety of the White Willow and 2 other willows, called, for simplicity, ‘Tristis’ which means ‘sad’. It sometimes has the name ‘Chrysocoma’ which means ‘golden-haired’. It is a male clone. It is common along rivers and in parks and gardens. It is one of the first willows to come into leaf, in March.
The Goat Willow (Salix caprea) is a shrub or small tree also known as Pussy Willow and Great Sallow. It is native to Europe (including Britain) and Asia. In Britain it is found everywhere in woodlands, scrub and hedgerows. The leaf is different from many other willows being oval shaped and with a tip that is bent sideways.The male catkins are yellow when full of pollen in March and April. The female catkins are green in April and shed fluffy seeds in May. The bark has criss-crossed ridges
The White Willow leaf is not as long as the Crack Willow. It has long white hairs on the upper surface. The leaves hang down and have a silvery-white appearance.
Grey Willow leaves are alternate and the shoots have stipules. These are tiny leaves at the base of full size leaves which identify the Grey Willow from other common willows.
The leaf is long and thin. The Weeping Willow is the first willow to come into leaf in Spring.
The Goat Willow leaf is oval-shaped and twisted at the end.
Close-up of the White Willow male catkin in April, showing the yellow ‘anthers’ before releasing pollen
Grey Willow male catkin in March showing the yellow pollen.
Weeping Willow male catkin March.
Goat Willow male catkins at the end of March. They come out before the leaves.