Aromatic Aster

Aromatic aster is the last thing to bloom in most gardens, opening sky-blue flowers in October after the other fall perennials have finished. This native, Symphyotrichum oblongifolium, grows 1 to 3 feet tall and wide in full sun to part sun, hardy from Zone 3 through Zone 8, and blooms the first season after planting. The flowers are lavender-blue with yellow centers, carried thickly on stiff branching stems. Bloom holds for weeks into fall and often runs until frost, which makes it one of the last nectar sources available to bees and late-flying butterflies. Asters are a keystone genus, and this species draws unusually large numbers of native bees, including several specialist bees that feed on nothing else. The foliage gives off a clean balsam scent when crushed or brushed against, and that is what keeps deer and rabbits off it. It is one of the few asters they reliably leave alone. This is a dry-soil plant, unlike the New England asters. It grows wild on limestone glades, rocky slopes, and prairie edges, and it wants lean, well-drained ground and full sun. Rich or wet soil makes it grow soft and flop. It handles drought, poor soil, and moderate road salt once established, and spreads slowly by stolons into a wider clump.