Erigeron
The fleabanes are a large genus, over 400, half of which native to North America, but not grown as much as asters and relatives. However they provide aster-like flowers and colour, much earlier in the year (late spring) and later on if cut back hard. Good for cut flowers and an excellent nectar source for insects. Good gardenworthy species are E. annuus, E. karvinskianus and E. glaucus. Grow in a reasonable soil and with no overhead competition.