Sky-blue aster
Sky-blue aster (Symphyotrichum oolentangiense) closes out the prairie bloom calendar with clouds of pale blue flowers in September and October. On dry uplands where New England aster struggles, it is the late-season nectar backbone for bees preparing for winter.
Why landowners plant sky-blue aster
- Blooms later than nearly everything else — critical for late bumble bee queens.
- Extremely high seed count per pound, so a tiny rate delivers a lot of plants.
- Handles dry, thin soils and partial shade at savanna edges.
- Satisfies the fall bloom-period requirement in CP42 mixes.
Site fit
Dry to dry-mesic upland prairie, savanna edges, and thin soils over gravel or bedrock. It tolerates light shade better than most prairie forbs, making it useful in oak savanna restorations.
Establishment
Dormant-seed for natural stratification. Seed is tiny — surface-sow and cultipack, never bury. Expect low rosettes in year one and reliable bloom by year three.
Management
Fire-tolerant. Fall burns can reduce seed set, so favor late-spring burn rotations where asters are a management target.
CRP practice fit
Fall bloom-period species in dry and mesic pollinator mixes.
Diversity forb in upland grass mixes.
Late-season nectar in prairie strips.
Featured mixes with sky-blue aster
Pairs well with
Little bluestem · Stiff goldenrod · Rough blazing star · Sideoats grama
Frequently asked questions
Very little. At roughly 1.2 million seeds per pound, 0.03 to 0.10 PLS pounds per acre puts tens of thousands of seeds on the ground.
It tolerates partial shade better than most prairie forbs, which makes it a good fit for savanna and woodland-edge plantings.