Spiraea douglasii, or Douglas Spirea (also called Hardhack or Western Spirea), is a fast-growing, native North American deciduous shrub known for its spiky, fragrant pink flowers in summer that attract pollinators, dense thicket-forming habit, and ability to thrive in moist to wet soils, making it great for rain gardens and streambanks but potentially invasive elsewhere. It features green, toothed leaves that turn yellow/orange in fall, and persistent seed heads provide winter interest, offering food and cover for birds.