Ceanothus sanguineus Pursh
Probably collected near Hungery Creek along the Lolo Trail in Idaho Co., Idaho, on 27 Jun 1806. (Source)
The Oregon Teatree is an open erect, loosely branched shrub up to 10 feet tall with slender, red branches with . slender, smooth, and purplish-red colored bark. The leaves are simple, alternate, deciduous, ovate, 1 to 3 1/2 inches long, thin, dark green and glabrous above and paler below, margins serrated, 3-veined from the base. It has small white flowers borne in large, dense clusters up to 4 inches long. The fruit is small, 3-lobbed, rounded capsule up to 3/16 inches in diameter. Its twigs are slender, smooth, purplish-red in color and the buds often stalked.
The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires dry or moist soil. This shrub grows best on relatively moist slopes in the open or in partial shade and is often most prominent at mid-slope. It is found reported at 2,400 to 4,000.