It may occur on sparsely vegetated surfaces or spreading over dense tundra vegetation. It grows in most arctic habitats including hummocks in wet sphagnum bogs and sedge meadows, polygonal tundra, solifluction slopes, snow beds, margins of pools, beach ridges, shaley and gypsum ridges, gneissic cliffs, colluvial slopes, talus slopes, imperfectly drained calcareous silty till, muddy salt flats, frost-heaved clay polygons, dry calcareous gravel, and coarse sandy soil. Plants are often heavily browsed by muskox and arctic hares. Salix arctica is a dwarf shrub, sometimes with long trailing branches that root where they touch the surface. Leaf size and shape are highly variable but the abaxially surface of the leaves is always glaucous and usually clothed with long, straight, appressed hairs that may persist as a 'beard' at the tip, the margins are entire.
Floral bracts are dark brown and clothed with long, straight hairs.
This circumpolar species is morphologically polymorphic and nomenclaturally confused. Many botanists studying the flora of the Arctic Archipelago have collected what they thought were two or three species of Salix to find on their return that they were all S. arctica . While the phytogeographic pattern of these three races is appealing they are actually very difficult or impossible to separate morphologically. Others have also reported environmental modification of S. arctica . In light of this evidence the possibility that the complex morphological variability within S. arctica may be ecophenic or ecotypic deserves study.