Willows

Goat willow
Salix caprea

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Goat willow belongs to the genus Salix and is a member of the willow family (Salix).

Goat willow (Salix caprea) is a deciduous tree growing to 12m and flowering March to April.

Lifespan: Long lived; 150–300 years.

 

Characteristics

Often growing as a many stemmed shrub or tree. Bark is grey-brown and fissured with age. Twigs are hairy at first becoming smooth. Leaves are alternate, oval with pointed tips (5–12cm), hairless above, densely grey-woolley below, irregular wavy margins and short leaf stalks. Stipules may be present at the leaf base.

Goat willow is dioecious, which means that male and female flowers grow on separate individual trees. Flowers appear before the leaves. Male flowers are grey, stout, oval catkins turning yellow when ripe with pollen. Female flowers are longer, green at first, developing into woolly seeds. Goat willow is wind pollinated.

Most willow species can also reproduce vegetatively; mature trees produce new ones as the branches reach the ground and take root.

Goat willow
Goat willow leaves

Distribution

Native in the UK. Widespread and common in woodland, hedgerows and scrub; quickly colonising waste ground. Found usually on damper, more open sites, near lakes, streams or canal sides.

In some areas it can be quite rare and has been replaced by hybrids.

There are a large number of native willow species native in the UK and many hybridise with one another, making identification difficult. Goat willow frequently hybridises with its close relative the grey willow (Salix cinerea).

In general, willow species are ecologically valuable in helping to stabilise river banks and prevent soil erosion. They can be used in restoring areas with degraded soils.

Human value

Goat willow timber is very soft, yellow-buff in colour. It has limited commercial value due to its small size. It is not ideal for weaving as its twigs are brittle. It was once used to make clothes pegs and the foliage was used as a winter feed for cattle.

Goat willow is an ideal species to coppice, being fast growing and of high wildlife value. It also produces good wood fuel.

Willows are important medicinal plants. The bark of all Salix species contains salicin; a compound which can relieve pain and fever and from which aspirin was derived.

The broader leaved species of willow, which include goat and grey willow, are sometimes referred to as ‘sallows’; goat willow as ‘great sallow’ and grey willow as ‘common sallow’. Both goat and grey willow are also sometimes nicknamed ’pussy willow’ for their silky grey female flowers which resemble a cat’s paws.

Goat willow flowers
Goat willow

Wildlife value

Willow trees in general are very important for wildlife and collectively support vast numbers of insects and notably moth species.

Goat willow supports a number of micro-moths and larger moths such as the sallow kitten, sallow clearwing, dusky clearwing and lunar hornet clearwing moth. Goat willow is also the primary food plant for the purple emperor butterfly.

Goat willow flowers provide both pollen and nectar for bees, insects and nectar-feeding birds such as blue tits in the critical period of early spring.

Due to the amount of insect inhabitants the tree is popular with many birds as a foraging site.

Management

A light-loving, fast growing hardy pioneer species which rapidly colonises open ground, especially in damp places. It can tolerate moderate shade.

Goat willow can be found on much drier (well-drained) soils than many of the willow species and is thought of as more of a woodland willow. However, it will still grow better in damper locations and at woodland edges where there is more light.

Seeds ripen May to June and are quickly blown away by the wind so you need to collect at just the right time. Seeds only remain viable for a few days so they must be sown straight away. They do not require any dormancy or pre-treatment. Goat willow can also be propagated from soft or hardwood cuttings.

Goat willow may be attacked by gall-forming parasites such as the beetle Saperda populnea. It may be affected by the fungal pathogen willow anthracnose (Drepanopeziza sphaerioides) and a rust which affects leaves and stems (Metelampsora).

Goat willow may be susceptible to watermark disease caused by a bacterium Erwinia salicis which can seriously threaten commercially grown willow.

The high insect load of goat willow may lead to heavy defoliation. Deer browsing may also be an issue. It is thought that deer prefer willow over many other trees; possibly because of the salicin content.

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Goat willow flowers

Grey willow
Salix cinerea

Grey wilow leaf

Grey willow (Salix cinerea) is also a member of the Salix genus. It is a deciduous tree growing up to 10m and flowering March to April.

Grey willow has characteristics which are subtly different from goat willow and the two species frequently hybridise. Their human use, timber type and wildlife value is very similar.

Characteristics are similar to goat willow, with second year twigs showing many long raised ridges (peel the bark to see this). Leaves are very variable, oblong and sometimes more rounded at the tip, tapered to the base, 2–9cm, downy above when young and downy below.

There are two sub-species of grey willow: ssp cinerea, with leaves soft woolly grey below and no rusty hairs, common only in east England; and ssp oleifolia, with leaves only downy on veins below when mature with some rusty hairs developing in late summer, common in most of the UK.

Grey willow is commonly found in wet woodland, near rivers, lakes and streams.

Seeds ripen May to June and are quickly blown away by the wind so you need to collect them at just the right time. Seeds only remain viable for a few days so they must be sown straight away. They do not require any dormancy or pre-treatment. Grey willow can also be propagated from soft or hardwood cuttings.

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Photographs © Forestry Commission