Subalpine spiraea (Spiraea splendens) cheers the sunny summer slopes and meadows with mounds of candy-colored, clove-scented blooms, followed by golden autumn foliage.
Blooms
Densely packed clusters of flowers atop each stem result in subalpine spiraea’s binomial synonym, S. densiflora. Their deep pink hue complements their intense, spicy scent that lures pollinators to their nectar. The multitude of stamens1A stamen is the male reproductive structure of a flower, consisting of an anther in which pollen is produced and usually a slender filament that attaches it to the flower. An individual flower typically has many stamens. bristling beyond its petals lend the flower heads a soft, fuzzy appearance and likely render it impossible for visiting bees and butterflies to avoid their service as pollinators. After pollination, the individual flowers form tiny, horned fruits that remain in dry, brown clusters resembling the bloom that bore them.
Plant Features
Subalpine spiraea’s tough, woody stems form neat, knee-high shrubs up to about three feet/one meter in height. Its simple2Leaves that are simple are not divided into lobes or individual leaflets. leaves alternate up reddish stems and are oval in shape, usually wider in the center or near the end, and slightly toothed or scalloped along the edges, again more so near the tips. In autumn, the deciduous, slightly bluish foliage turns golden as the chlorophyll fades.
Similar Species
Subalpine spiraea’s distinguishing features are its relatively flat umbels3An umbel is a flower cluster with all branches originating at the same point, usually resulting in a rounded or domed form. of deep pink blooms, broadly oval leaves, and height not exceeding three feet/one meter. In Western Washington, it shares habitat with two similar cousins, Douglas’s spiraea (or, confusingly, rose — but not rosy — spiraea) (S. douglasii), which has much more elongated bloom clusters and leaves and can grow to twice as high, and pyramid spiraea (Spiraea x pyramidata), which has looser, white to pale pink blooms somewhat intermediate in form between subalpine and Douglas’s spiraea.
Range and Habitat
Subalpine spiraea ranges throughout North American’s Olympic, Cascade, Sierra Nevada, and northern Rocky mountains from British Columbia south to California and east into Montana, Nevada, and Wyoming. In Western Washington, it is particularly common on the west slopes of the Cascades. As suggested by its common name, look for subalpine spiraea at mid- to high elevation in moist meadows and open forest generally below the treeline, as in the accompanying habitat photo.
Gallery
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