Close-up of the inflorescence (and a pollinator) of birch-leaved spiraea (var. lucida) as seen from Steptoe Butte in eastern Washington................. June 22, 2009.
White spiraea is an attractive, deciduous shrub with spreading to erect stems from 40-70 cm high. The bark of older stems is reddish. It spreads fairly easily via rhizomes. The leaves alternate on the stems. They are oval-shaped or obovate and 2-7 cm long. They are dark green on the upper surfaces and lighter on the lower surface. The blades are often widest above the middle, and they are irregularly and coarsely-toothed from the tip to the middle of the leaf.The inflorescence is a flat-topped cluster of white flowers about 3-12 cm across known as a corymb. Although commonly white, the small flowers may also be tinged with pink or purple. The flowers are saucer-shaped and about 5 mm across. Each flower has 5 tiny petals and about 25-50 long stamens. The fruits are beaked, pod-like capsules about 3 mm long.
White spiraea is found from on open to wooded slopes or on valley bottoms along streams and the margins of lakes.. It may be found between sea level and 4000' from the Pacific coast to the Cascades, and may be found up to 11,000' in the Rocky Mts..
White spiraea may be found from southern British Columbia south along the Cascades to north central Oregon and east to Saskatchewan, South Dakota, and Wyoming. It is also found in Asia.