sandbar willow

not listed

NNR - Unranked

SNR - Unranked

not listed

FACW - Facultative wetland

FACW - Facultative wetland

FACW - Facultative wetland

Sandbar willow is a tall, deciduous shrub, rarely a small tree, that rises on numerous stems. It can be 13′ to 21′ in height and up to 3½″ in diameter at breast height. Unlike other willows, it does not form a root crown. The root system is spreading and horizontal. Additional aerial stems rise from buds on roots near the surface (suckering). It often forms dense colonies.

The stems are erect. The bark is gray or yellowish-brown and smooth on young stems; gray and relatively smooth on mature stems; gray or brown, somewhat rough, and sometimes finely plated or ridged on older stems.

Branches are slender, grayish-brown or reddish-brown, ascending, and flexible at the base. First year secondary branches (branchlets) are greenish-brown or yellowish-brown and sparsely to densely hairy. They do not have a whitish waxy coating (glaucous). They sometimes become hairless or almost hairless as they age. Second-year branchlets are reddish-brown or grayish-brown and hairless. Lateral buds are blunt at the tip. They are covered by what appears to be a single scale but is actually two opposite scales that are fused together. The scales are not sticky.

The leaves are alternate and linear to narrowly oblong. The largest mid-stem leaves are 2⅜″ to 6¼″ long and ⅛″ to 7 ⁄16″ wide, mostly 11 to 19 times as long as wide. They are on short leaf stalks (petioles) that may be 1 ⁄32″ to ⅜″ long but are usually no more than 3 ⁄16″ long. The petioles may be hairy or hairless. They do not have a pair of glands where they attach to the blade. At the base of the petiole on late-season leaves there is a pair of minute or well-developed, leaf-like appendages (stipules), but these fall off early and are often missing. On early-season leaves the stipules are rudimentary or absent. The leaf blade is wedge-shaped at the base and tapered at the tip with straight or somewhat convex sides at the tip. There is a single well-developed midvein. The upper surface is medium green and slightly glossy. It may be sparsely to moderately hairy, especially along the midvein, or completely hairless. The lower surface is similar in color, not glaucous. The margins are flat, not rolled under, and have 2 to 5 small, widely-spaced, sharp, forward-pointing teeth per centimeter (⅜″). Young, unfolding leaves are reddish-green or yellowish-green and are sparsely to densely covered with long silky hairs on the underside.

Male and female flowers are borne in cylindrical clusters (catkins) on separate plants. Early catkins flower as the leaves appear beginning in early May. Male catkins are ¾″ to 2⅜″ long and ⅛″ to ⅜″ wide. They appear at the end of a leafy, ⅛″ to ¾″ long branchlet. Female catkins are ¾″ to 2¾″ long, 3 ⁄16″ to ⅜″ wide, and loosely flowered. They appear at the end of a leafy, ⅛″ to ¾″long branchlet. Late catkins appear as late as early July. They are on longer branchlets and often have short, secondary, lateral catkins.

The sepals and petals are reduced to a single, minute, nectar-secreting gland (nectary). Male flowers have 2 separated stamens with hairy white filaments and yellow anthers.

The fruit is a ⅛″ to ⅜″ long capsule with numerous seeds. The seeds are released early June to mid-August, and are dispersed by wind.

13′ to 21′

Wet to dry. A variety of habitats but especially sandy or silty flood plains, margins of lakes and ponds, marshes, sloughs, and dry sandy hills on prairies. Full sun.

Early May to early July

Sources

2, 3, 4, 5, 7, 8, 28, 29.

Native

Very common and widespread

Sandbar willow (Salix interior) hybridizes with narrowleaf willow (Salix exigua) where their ranges overlap in the western Great Plains. Sandbar willow is sometimes classified as a subspecies of the latter, Salix exigua ssp. interior. The area of hybridization is relatively small and the two species remain morphologically distinct. Most taxonomic authorities, with the notable exception of GRIN, retain the name Salix interior.