Spiraea douglasii is a species of flowering plant in the rose family. Common names include hardhack, hardhack steeplebush, Douglas' spirea, douglasspirea, It is native to western North America and is an invasive species in other locales.
The specific epithet douglasii honors Scottish botanist David Douglas, who is noted for cataloguing numerous species native to the American west.
Description
Spiraea douglasii is a woolly shrub growing tall from rhizomes, forming dense riverside thickets. It has spread to many other places as an invasive species. It was introduced to Europe in 1803, and is especially invasive in Denmark and Latvia. It is also found in France, Ireland, Slovenia, Sweden, the United Kingdom, Belgium, Germany and Poland.
It occurs most often in riparian habitat types, such as swamps, streambanks, bogs and mudflats. It grows best on moist or semiwet soils with good drainage. It tolerates a variety of soil types as well as gravelly substrates.
Spirea is shade-intolerant, and therefore grows primarily in open marshes among sedges, horsetails, wild blueberries, and other swamp flora, The plant provides nesting habitat for birds like marsh wrens and is a component of grizzly bear habitat.
The plant is used as an ornamental in landscaping, where it grows best in sunny, moist places. Spirea is recommended for riparian revegetation projects in the Pacific Northwest, as it is hardy and grows quickly.