Symphyotrichum grandiflorum

A native aster with a regional accent. Most of the asters Americans plant are wide-ranging species that turn up from Maine to Texas and read essentially the same wherever they grow. Symphyotrichum grandiflorum is more particular, with a native range small and specific: the Atlantic Coastal Plain of Virginia and the Carolinas, plus the Piedmont of the Carolinas, and little more. A few hundred miles of sandy roadsides, dry pine-oak woods, abandoned fields, and forest edges from the Tidewater into the rolling country west of the fall line. For a gardener in the Carolinas or Georgia, this is one of the few asters that is genuinely here, a piece of the actual Atlantic Coastal Plain flora rather than a borrowed prairie species filling in for a missing native.

The flower is the show. Heads an inch and a quarter to an inch and a half across, large for a wild aster, hence the species name grandiflorum, with twenty to thirty narrow ray florets in a deep, saturated violet-purple around a tight golden disk. The color carries enough blue to read cool and enough red to read warm, the kind of saturated violet that catches autumn light beautifully. The flowers open at a useful time, October into November, when most of the other asters have already finished and the garden is otherwise leaning toward seed heads, late grasses, and the first frost. Among native asters, grandiflorum is one of the latest to bloom and the largest-flowered, two genuine differentiators the more common species cannot match.

The plants stand one to three feet tall on stiff, hairy, upright stems, with narrow, lance-shaped leaves and lower clasping foliage. Not a soft, billowy, fall-flowering aster, but an upright, structural one, more architectural than romantic. Dry, sandy soils suit the plant well, and poor conditions that defeat showier perennials are taken in stride, which is part of why grandiflorum has persisted along Coastal Plain roadsides where the native communities have largely disappeared. A long list of late-season insects works the flowers, including specialist Andrena bees that depend on Symphyotrichum and a few related genera for their pollen; without late asters, these bees lose their season.

For the gardener building a late-fall pollinator garden, anyone planting the actual flora of the Carolinas rather than a generic native mix, or the late-season designer wanting a structural, drought-tough, deep-purple punctuation when most other asters are spent, grandiflorum earns a place.