The large family of asters has had to be subdivided in recent years. As a result, the Aster genus proper now consists only of Eurasian species; the American asters have been divided into some ten new families. The largest of these is Symphyotrichum with about 90 species, including the blue wood aster.
Asters are fine autumn perennials that have been cultivated to produce larger blossom than the wild varieties. The range of wild species and cultivated varieties is huge, and growers in the Northern countries should choose ones that manage to flower in the brief summer and are not too prone to disease.