Pacific Willow

Handsome and fast-growing, willow can also restore damaged soil and fight back invasive weeds.

Credit: Richard Hebda

Willows are widely respected for their role in the landscape.

Weeping willow (Salix babylonica) graces many an old farmyard and can be found arching tranquilly over stream and pond in quiet corners across North America. In fact, this singular foreign willow dominates the horticultural world almost to the exclusion of all other species, yet we in British Columbia are blessed with an unimaginable richness of willows (50 species, to be exact). In particular, the Pacific willow (Salix lucida) offers an admirable alternative to weeping willow for moist sites, as well as the power to heal landscapes scarred by our overzealous attempts to transform them.

Pacific willow is probably familiar to many of you as one of our most common swamp species. It grows as a tall shrub or small tree with mostly erect stems reaching to 15 m (50 ft.) in height. Young twigs are a glossy yellowish green, older branches pale brown, and the yellowish-brown old bark may be fissured, while the buds resemble little yellow duckbills. This willow’s attractive 5- to 15-cm-long (2- to 6-in.) leaves are distributed in an alternate manner along its branches. Shaped like lance points, they taper to a graceful tip, showing margins lined with tiny teeth, an upper surface of a striking glossy green (hence the alternate common name of shining willow) and a contrasting lower surface of pale green. At the base of the petiole are obvious, rounded, ear-like structures called stipules.

The Pacific willow’s flowers are borne in an elongated cluster called a catkin, appearing at the same time the leaves emerge or after, unlike some of our pussy willows, including Hooker’s willow (Salix hookeriana) and Scouler’s willow (Salix scouleriana), both of which are also good natives for the garden. The catkins are generally yellowish, turning pale brown with age before they drop. The 7-cm-long (3-in.) male catkins consist simply of bracts (highly modified leaves), each at the base of a cluster of five stamens. Female catkins have many individual flowers consisting of a bract and a single green pistil that matures into a pale-brown capsule. In late spring to early summer the capsule splits and fluffy white seeds drift gently to the ground to germinate in the moist soil.

Pacific willow occurs throughout British Columbia, excluding high elevations. The range extends to the prairies and southward into California, and related willows grow as far east as Labrador. You will find this willow in most wet situations with quiet standing water, including lakeshores and ponds, along stream and riverbanks, on flood plains and in moist meadows and swamps. Often it forms tall dense thickets. Willows were widely used by First Nations for many purposes, including medicinal ones. Specifically, the Thompson peoples used Pacific willow to make splints for broken limbs. Water from boiled willow bark was used to treat injuries, while the boiled bark could be tied on directly as a poultice. And the Stó:lõ people of the Fraser Valley are said to have drunk a decoction of the inner bark to treat pneumonia. Willow bark, incidentally, is known as the original source of the active ingredient in aspirin (acetylsalysilic acid for Salix).

First Nations also found other practical uses for the Pacific willow. The flexible branches were well suited to making fish traps, frames for sweat houses and rims for birch bark baskets. The Stl’atl’imx people of the Fraser Canyon used dried Pacific willow wood as both drill and hearth to make friction fires. Twine and rope, as well as delightful dolls, were fashioned from willow bark throughout our region.

In your own garden, Pacific willow is well suited to moist sites in larger lots where it can be grown for the rich glossy display of its leaves and its seasonal show of catkins. Unlike weeping willow, it remains relatively constrained, not reaching outward too far with its branches or roots. Regular pruning of the old stems keeps the form tidy and leads to bright new branches that are especially attractive in early spring. Of course, if you have a pond or ditch in need of a tree, Pacific willow is ideal. Moist sites under power lines are also appropriate because the tree crown can easily be kept from interfering with the wires. One of this willow’s greatest attributes is its value as a species for restoring damaged streamsides and wetlands. When whips of young growth, cut in summer to fall, 1.5 to 2 m (5 to 7 ft.) long, are buried deeply, such that only half a metre (1.5 ft.) of stem shows above the ground, they will root very well and shoot out new growth within a year. Unrooted stems establish as well as rooted ones, so stem cuttings are an ideal way to propagate this willow for your garden. With its rapid growth it also makes a fast-growing hedge or screen and shades out unwanted weedy grasses and other herbaceous plants. So if you have a stream, pond or ditch, try our native Pacific willow. This refined relative of weeping willow will not only provide a graceful display but will also bind the soil and fight back rank invasive weeds, too.

The following plants are hardy to the zone number indicated: • Salix babylonica – zone 5 • Salix hookeriana – zone 7 • Salix lucida – zone 2 • Salix scouleriana – zone 2 An expert on native plants, Richard Hebda is curator of Botany and Earth History at the Royal British Columbia Museum in Victoria.