Salix nigra aka Black Willow

Salix nigra, or black willow, is a fast-growing deciduous tree. It belongs to the willow family, Salicaceae. Its native range runs from eastern Canada to Mexico. It grows beside rivers, ponds, marshes, and other wet ground. In the United States, it occurs from Maine to Florida. Its range also reaches Minnesota, Colorado, and Texas.

Garden trees often reach 30–60 feet [9.1–18.3 metres] tall. They can spread to 60 feet [18.3 metres]. North Carolina State reports heights of 70–80 feet [21.3–24.4 metres]. Trees in ideal sites can reach 140 feet [42.7 metres]. One or more curved trunks support a broad crown. The crown may look rounded or uneven. Older bark becomes dark brown or black, with deep furrows. Loose scales give the bark a rough look. Slender twigs are orange-brown and break off with ease.

The simple leaves grow in an alternate pattern along stems. They are narrow, lanceolate, and edged with fine teeth. Leaves measure 0.25–0.5 feet [0.08–0.15 metres] long. Their green colour turns a muted greenish-yellow in autumn. Male and female flowers grow on separate trees. Small yellow-green flowers form catkins as new leaves appear. North Carolina flowering runs from March to May. Chicago records bloom from March through June. Reddish-brown capsules hold many small seeds with soft hairs. Wind carries the seeds away from the parent tree. Fruits appear from April to June in North Carolina.

Black willow needs soil that stays moist or wet. It grows in many soil types with enough water. Full sun suits it best, though it accepts part shade. It withstands floods and the build-up of silt. Chicago lists it for USDA zones 2–8. Prune when needed in late winter or early spring. Cutting it to ground level every two or three years keeps it small. Its shallow roots help hold soil on wet banks. The tree also feeds the larvae of several butterflies. Its wood has uses in crates, furniture cores, and utensils.

This tree needs much upkeep and suits few home gardens. Its roots may enter drains or sewer pipes. Weak wood can split under wind, snow, or ice. Fallen leaves, twigs, and branches create litter. Pests include aphids, leaf beetles, sawflies, caterpillars, and borers. Diseases include blights, mildew, leaf spots, crown gall, and cankers.