Not to be semantically confused with : Goat's-Rue (Galega officinalis), Goat's-beard (Tragopogon pratensis) or
Goat Pea (Securigera securidaca), [plants with similar names belonging to differing families]
Grey Willow and Goat Willow collectively are known as 'Pussy Willow' because of their silky hairy buds in early spring.
Easily mistaken for Goat Willow (Salix caprea) (which also has 2 sub-species as does Grey Willow), the differences being:
But, the hybrid of Grey Willow with Goat Willow is common.
- If the bark is peeled off 2-year-old twigs, then the exposed surface is ridged on Grey Willow (but smooth on Goat Willow)
- The bark of Grey Willow grows darker and has shallower ridges than that of Goat Willow
- The leaves of Grey Willow are usually much smaller and between 2 to 3 times as long as broad and broadest beyond halfway to the tip
- Grey Willow (the much more common ssp. oliifolia sub-species - which is sometimes known as Rusty Willow) has fine felty hairs on the underside of the leaves and rusty-looking hairs along the veins on the underside of the leaf (whereas Goat Willow does not)
- The flowers on Grey Willow also start later than those of Goat Willow
- The softly-furry 'pussies' are slightly larger on Goat Willow
- Grey Willow is much less often found away from damp areas than is Goat Willow
It is native and a shrub or small tree growing to 6m high (15m max), thus usually smaller than the similar Goat Willow which is 10m high, 19m maximum.
Grey Willow exists as two sub-species:
- Salix cinerea ssp. cinerea (which is much less abundant and mainly occupies fens in a triangle between Burton on Trent at the centre, with Hull at the northern limit and Gravesend at the southern limit. Although in the last 10-15 years it seems to have departed from most of Norfolk and since the turn of the Century from most of Northern Ireland, it has however been spreading very slowly in apparently random isolated spots randomly throughout the UK since 2010). This species is usually persistently hairy. The leaves are dull and hairy (or not) on the upper surface and densely hairy on the underside. Leaf shape is mostly oblong or obovate. At low altitudes this species is found on marshes and fens.
- Salix cinerea ssp. oleifolia which is much the most widespread throughout the UK. The twigs become glabrous (hairless) as they grow. The leaves are mostly narrow-obovate or oblong and less glossy than those of ssp. cinerea and nearly glabrous on the upper surface. On the underside the leaves have grey hairs and some stiffer rust-coloured hairs along the veins. This sub-species is sometimes known as
Rusty Willow for that reason. It is found in wet places, woods, both lowlands and uplands. It is the commonest species of Willow in the lowlands.
Hybridizes with :
- Goat Willow (Salix caprea) to produce Salix × reichardtii
- Goat Willow (Salix caprea) +
Creeping Willow (Salix repens) to produce Salix × permixta
Eared Willow (Salix aurita) to produce Salix × multinervis
Eared Willow (Salix aurita) +
Dock-leaved Willow (Salix myrsinifolia) to produce Salix × forbesiana
Dock-leaved Willow (Salix myrsinifolia) to produce Salix × strepida
Dock-leaved Willow (Salix myrsinifolia) +
Dock-leaved Willow (Salix myrsinifolia) to produce Salix × phylicifolia
Creeping Willow (Salix repens) to produce Salix × subsericea