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Symphyotrichum cordifolium

The common Blue Wood Aster (of which ‘Avondale’ is a cultivar) is an herbaceous perennial native to a huge swath of north-central-eastern North America, and the counties in NC where it is reported represent the southeastern tip of its range. Found in dry to moist (well drained) deciduous woodlands and woodland borders, and sunny to semi-shaded areas along streambanks, it lends itself to cultivation in a wide range of shady garden transitional habitats where color and wildlife support are welcome. The flowers, from August to October, are composites typical of Asters, with bluish ray florets and light yellow disc florets that eventually turn purple. Grown in a sunny perennial bed, the plant habit is upright, but grown en masse along a shady forest edge, it tends to arch over in a sweep. Blue Wood Aster attracts a very long list of insects feeding on both flowers and foliage and where it is allowed to spread and is more decumbant and carpetlike, it provides cover for small mammals and ground nesting birds.

The flowers of the cultivar of Blue Wood Aster called ‘Avondale’ are reliably more blue than the straight species, and in our experience the deeper blue shades for both species and cultivar are encouraged by shady conditions. The USDA plant distribution map linked below is for the species.

Key Info

Scientific Name: Symphyotrichum cordifolium (L.) G.L. Nesom (synonym Aster cordifolius) cv. 'Avondale'
Common Names: Blue Wood Aster, Heart Leaf Aster, Broad-leaf Aster
Moisture Requirement: , ,
Bloom Times: , ,
Flower Color: Pale to deep blue, lavender, occasionally white with yellow centers turning purple

Additional Info

Habit: Smooth, branched, upright-arching stems to 3+ feet tall, branching occasionally in the upper half. The terminal panicle is ½-1½ feet long, longer than it is wide and it is more broad toward the bottom than the apex. When upper lateral stems are present, they support much smaller panicles. Blue Wood Aster overwinters as a rosette. The root system is fibrous and short-rhizomatous.
Height: 2' to 3'
Spread: 2' to 3'
Soil Conditions: Soils that are rocky to loamy, but generally rich; dry to moist, well-drained, acid soils; clay, loam, sand .
Leaves: The leaves are not all uniform. They are alternate, up to 5 inches long and 3 inches across (excluding the petioles), becoming smaller as they ascend the stems. The lower leaves are cordate, while the upper leaves are more oval, with coarsely serrated margins. The petioles of the leaves can be almost as long as their blades (up to 3½ inches), sometimes slightly winged, becoming shorter among the upper leaves. To add to the confusion about the leaves, there are also elliptic or linear/oblong leafy bracts up to 1 inch long among the branches of each panicle.
Flowers (or reproductive structures: The upper stem terminates in a panicle of flowerheads. Each small flowerhead is about ½ inch across, consisting of 7-15 lavender, light blue or (less often) white, linear-oblong ray florets that surround a similar number of disk florets. The corollas of the disk florets are initially cream-colored or pale yellow, but they later turn purple to reddish purple with age.
Fruit: The florets are replaced by oblong achenes with small tufts of white hair. Individual achenes are 0.1 inches long.
Natural Distribution: Open wooded slopes, along the banks of streams, along the borders of beech–maple and oak–hickory forests, as well as in disturbed areas such as along roadsides and ditches.
USDA Hardiness Zone: 4 to 8
USDA Wetland Indicator Status in NC: Not available
Pollination: Mostly bees.
Wildlife Connections: The nectar and pollen of the flowerheads attract bees, wasps, flies, butterflies, skippers, and beetles. Caterpillars of butterflies and moths as well as other insects (leaf beetles, the larvae of leaf-mining flies and fruit flies, various plant bugs and leafhoppers) feed on the foliage as well as on the flowers, developing seeds, stems, and roots. Mammalian herbivores, including rabbits, groundhogs, deer, and livestock, browse on the foliage and Wild Turkey and Ruffed Grouse eat both the foliage and seeds. (Illinoiswildflower.org)
Propagation: From seed or division.