Cascara Cascara Buckthorn

Cascara is a native understory shrub-tree of moist bottomlands and forest edges in Western Washington, a deciduous species with smooth gray bark and broad, oval leaves. The small greenish-white flowers appear in clusters in late spring; the fruits are berry-like, maturing from red to black. The tree rarely exceeds 25-30 feet in managed landscapes and is often much smaller and multi-stemmed. Cascara's bark has long been harvested for laxative production (the bark must be aged for one year or heat-treated before use to avoid severe purgative effects). The tree's modest stature and inconspicuous flowers make it easily overlooked, yet it is an important food and cover plant for wildlife.

In Western Washington, cascara is a useful native understory species for moist, shaded sites where it performs steadily without demanding attention. The tree tolerates full shade to part sun and is particularly valuable in riparian restoration where its presence gradually replaces the more aggressive red alder. Growth is slow to moderate, and the tree's modest size makes it suitable for mixed shrub-tree plantings. The tree has few serious pests or diseases and is reliable in appropriate sites. Avoid harvesting bark from wild or landscape trees; if you wish to use cascara medicinally, grow it specifically for that purpose with a multi-year management plan (bark must age one year post-harvest). For Western Washington lowland and foothill sites with moist soils and some shade, cascara is an excellent native alternative to ornamental understory shrubs; it provides wildlife value and ecological function while requiring minimal maintenance.