Common name: blue arctic willow, purpleosier willow
Hardiness Zone: 3-6
Height: 6-10' (sometimes to 20')
Description: S. purpurea features blue-green leaves, and first season's growth matures to red-purple stems. Light green flowers bloom in late April, eventually with ornamentally insignificant fruit. It is native to Europe, Northern Africa, and Central Asia but introduced across the eastern and mid-west US. It is tolerant of most soils and urban pollution, including some standing water.
The species can be useful for erosion control on stream or riverbanks susceptible to ice or other mechanical damage. It can be pruned back to 4"-2' from the ground if it becomes too large, and a dwarf variety (5' at maturity) is available for use as an ornamental.
"Purpleosier Willow Salix purpurea". USDA Plant Guide. https://plants.usda.gov/factsheet/pdf/fs_sapu2.pdf
"Salix purpurea - Purpleosier Willow". Ohio State University Plant Facts. https://plantfacts.osu.edu/pdf/0247-989.pdf
"Salix purpurea Purpleosier Willow". University of Conneticut Plant Database. http://www.hort.uconn.edu/plants/detail.php?pid=447