Black Hawthorn

Black hawthorn is a native small tree and shrub of Western Washington's woodlands and streambanks, a deciduous species with white flowers in spring and small black fruits in fall. The bark is gray and slightly furrowed. The leaves are oval, toothed, and dark green. The thorns are sharp and formidable (unlike ornamental hawthorns, which have smaller spines). The flowers appear in clusters of 5-15, each white and about half an inch across. The tree reaches 15-30 feet in open sites and grows more shrubby in shade or disturbed conditions. The dense form and spiny branches make it valuable for wildlife screens and security barriers.

In Western Washington, black hawthorn is a useful native species for riparian restoration, wildlife habitat, and erosion control. The tree tolerates wet to moist soils and partial shade to full sun. It grows at a moderate rate and is relatively long-lived (80-100+ years) compared to other pioneer species. The tree is susceptible to various fungal canker diseases and fire blight (Erwinia amylovora), a bacterial disease that thrives in our wet springs. Prune infected branches below the disease canker and sterilize tools between cuts. The sharp thorns require careful planting away from pedestrian traffic. The white flowers appear in May-June and attract pollinators; the black fruits ripen in late summer and fall, providing food for birds and small mammals. For riparian zones, security plantings, and wildlife habitat, black hawthorn is an underutilized native that deserves more landscape attention; its modest stature, long life, and ecological value make it a practical choice where you can accommodate its spiny character.