The osoberry is among the earliest forest plants to leaf out, to blossom, and – starting in midsummer – the first to lose leaf chlorophyll, turn yellow and fall. Early start, early finish.
Quoting from the venerable Pojar, Plants of the Pacific Northwest Coast:
General: Shrub or small tree 1.5-5m tall (4-15 feet), one of the first plants to flower in the spring; bark bitter, purplish brown.
Leaves: Alternate, deciduous, pale-green, broadly lance-shaped, 5-12 cm long, not toothed, strong cucumber-like smell when crushed.
Flowers: Greenish-white, about 1 cm across, male and female flowers on separate plants (“dioecious”) , 5 petals, 15 stamens in 3 distinct series somewhat bell-shaped, appearing very early in the year (usually before the leaves), unusual fragrance (something between watermelon rind and cat urine (!); in 5-10 cm long clusters hanging from leaf axis.
Fruits: peach-colored, ripening to bluish-black with a whitish bloom, like small plums, about 1 cm long, edible but bitter, with a large pit.
Ecology: Dry to moist, open woods, streambanks, open areas (especially roadsides); low elevations.
Notes: Alternate common (settler colonialist) name is Indian Plum, Linnaean name is Oemieria cerasiformis. May be fertilized by hummingbirds. O. cerasiformis is the only member of the genus. “cerarisiformis” means “cherry shaped” in Latin.