close-up shot of small flowers of daisy-like blue wood aster aster cordifolius or symphyotrichum cordifolium. flowers are blue

america aster attractive autumn beautiful bloom blooming blossom blue botanical botany center closeup common cordifolium cordifolius cultivar daisylike delicate fall flora floral floriculture flower flowering flowers garden gardening head heartleaf macro nature north outdoors plant purple small summer sun sunlight symphyotrichum wood woodaster yellow