[Spiraeas: The Genus Spiraea in the Columbia River Gorge of Oregon and Washington]

Pyramid Spiraea

Spiraea x pyramidata

Synonyms: Spiraea betulifolia x douglasii, Spiraea tomentulosa ssp. pyramidata

The photo above shows the pyramidal inflorescence of pyramid spiraea as seen between Little Bowaman Creek and Canyon Creek in the Klickitat Wildlife Area..........June 19, 2016.

Photo at right of Spiraea pyramidata from along the Swauk Pass Highway through the Wenatchee Mts. of central Washington...........July 25, 1996.

Characteristics:

Pyramid spiraea is a spreading to erect shrub from 50-100 cm high which is fairly strongly rhizomatous. He herbage above and in the inflorescence is fairly hairy with the leaves ranging from smooth-surfaced to somewhat hairy below. The leaf blades are ovate-lanceolate to oblong-elliptic or oblong-lanceolate. The range from 2-7 cm in length and may be mostly entire to having teeth above the middle of the leaf.

The inflorescence is a roughly round to conical-shaped panicle about 10-20 cm long and 5-10 cm wide. The densely crowded flowers are white, although they may have a pink or lavender tinge especially in the bud. Each of the 5 petals is 2-2.5 mm long.

Habitat:

Pyramid spiraea is found on open and dry canyon slopes or on valley bottoms along streams.

Range:

Pyramid spiraea may be found from southern British Columbia south along the Cascades to northern Oregon and east to central Idaho.

In the Columbia River Gorge, it may be found between the elevations of 100'-3500' from near the western entrance to the gorge east to Hamilton Mt.

The photo above shows the pyramidal inflorescence of pyramid spiraea as seen on the eastern slopes of Mt. Adams..........August 25, 2005.

Paul Slichter