Spiraea is a genus of small shrubs of the family Rosaceae (rose). The genus consists of some 70-80 species, as well as many horticultural varieties of garden origin that have resulted from hybridization. Probably the most noteworthy of these hybrids is S. vanhouttei (bridal wreath spiraea), derived from 2 Asiatic species, S. trilobata and S. cantoniensis, which is widely cultivated in Canada and elsewhere for its spectacular spring blossoms. Spiraeas are deciduous, with simple leaves and generally dense clusters of small, white, pink or purple flowers. They are native to the north temperate zones of Eurasia and North America, generally growing on moist, wooded slopes and meadows. Canada has 7 native species, none of which are found all across the country. The most widespread, S. alba, occurs from Alberta to Newfoundland. One species, the western S. beauverdiana, extends northward to the Arctic Ocean.