Douglas aster is a rhizomatous perennial 1-3 feet tall. The one in my yard is currently in bloom (August), one of the few Puget lowland natives that puts on a show in late summer. Though it is a bit too exuberant for a small formal border, Douglas aster is a cheerful addition to a naturalized meadow or forest edge. It tolerates salt spray, and is a good source of nectar for bees and butterflies. Mine is tucked into a corner between some hardscaping, a large shrub, and the lawn, where overenthusiastic shoots meet the mower.
It’s not only plants that don’t stay put. In 1994 there was a worldwide study on the big, variable genus Aster, which concluded that North American Asters were not very closely related to the Eurasian type species. (Both the chromosomes and the achenes of the Eurasian species are larger and more symmetrical). So, someone went through the published literature to find the earliest alternate genus names. The largest group of North American species ended up in Symphyotricum.
In the Washington Flora Checklist, David Giblin writes “Symphyotrichum subspicatum is a weedy, highly polyploid species, probably of allopolyploid derivation from different combinations of species including S. chilense, S. eatonii, S. foliaceum, S. laeve, and S. spathulatum. Hybrids with S. hallii are known from western Oregon. The species passes into S. foliaceum in Southeastern Alaska.” The Jepson manual states that S.subspicatum is “highly variable; grades into S.chilense.”
In other words, once you get used to all the name changes, you can continue to amuse yourself by trying to define the plant.
The Jepson Manual, 2nd Ed. University Of California Press, 2012