Sky blue aster
Sun/shade: Full sun to part shade
Soil moisture: Dry to medium
Flowering period: September
Host plant for 12 caterpillar species
This well-behaved aster does not usually spread, unlike some aster species. Numerous blue-lilac flowers emerge in September and are beloved by butterflies. Adaptable to most soils as long as they're well-drained. Heavily mulched beds will prevent this short-lived perennial from reseeding, shortening its life in the garden.