Culture
Winter hardy to USDA Zones 3-7 where it is best grown in average, medium to wet, well-drained soils in full sun to part shade. Prefers full sun. Best in neutral to slightly alkaline soils. Thrives in moist soils, including intermittently flooded ones, but tolerates somewhat drier soils better than some other types of willows. Intolerant of dry soils. Grows well in sandy soils. Thrives in poor soils. Prefers cool summer temperatures. Struggles in areas with high summer heat and humidity such as the Deep South. Prune as needed in late winter to early spring. Plants may be cut to the ground every 3-5 years (more frequently if needed) to maintain a more vigorous and ornamental shape.
Noteworthy Characteristics
Salix purpurea, commonly known as purple osier or basket willow, is a dioecious, upright- rounded, multi-branched, deciduous shrub to 9-18’ tall and as wide. It is native to Europe and Northern Africa east to temperate central Asia and Japan. It was introduced into North America as a plant that would help reduce erosion along stream banks and lake shores. It has now naturalized in moist low-ground areas along streams, lakes, fens, swamps, sandy areas and depressions, primarily in southern Canada, the northeastern U.S., and the Great Lakes. Young shoots are initially purplish, but turn light gray to grayish-brown as they age. Narrow, linear to oblanceolate leaves (to 2-4” long but only to 1/3” wide) are lustrous blue-green above and pale green beneath with serrate margins from mid-leaf to tip. Catkins (to 1 1/4” long) appear each year in March to April before the leaves unfold. Each catkin contains tiny flowers in dense clusters. Catkins emerge reddish purple, eventually maturing to dark grayish white. After flowering, the catkins on female shrubs produce small seed capsules which split open when ripe (late spring to early summer) to release seeds.
The bark of this shrub is a source of salicin which is a chemical medically used in the treatment of pain in a manner similar to that of aspirin.
Genus name is the Latin name for this plant.
Specific epithet means purple in reference to the purplish male flowers and purple young stems.
‘Nana’, sometimes commonly called dwarf purple osier, is a small compact cultivar with purplish stems. It typically matures to 3-5’ tall. Leaves are typically narrower than those found on the straight species. It is often best grown as a clipped shrub to 3’ tall. ‘Nana’ from Latin means dwarf in reference to the small size of this cultivar.
Problems
Susceptible to numerous disease problems including blights, powdery mildew, leaf spots, gray scab and cankers. It is also visited by many insect pests including aphids, scale, borers, lacebugs and caterpillars. Wood is weak and may crack. Branches may be damaged by ice and snow. Litter from leaves, twigs and branches may be a problem. Shallow roots may clog sewers or drains and make gardening underneath the plants difficult.
Species plants can become overgrown and/or disheveled over time, at which point they may be cut back close to the ground.
Uses
Foliage, purple twigs and purple catkins are the main ornamental attributes of this shrub. It may be grown in moist soils along streams, ponds or in low spots in the landscape where other shrubs often falter. Specimen, group or mass. Good for erosion control. Hedge.
Flexible twigs are often used in basketry, hence the sometimes used common name for this shrub of basket willow.