Symphyotrichum lateriflorum aka Calico Aster

Symphyotrichum lateriflorum belongs to the daisy family, Asteraceae. This perennial lives for more than two years. Its names include calico aster and side-flowering aster. It is native from Canada to Veracruz, Mexico. It grows in woods across eastern and central North America. Older names include Aster lateriflorus and Aster diffusus. It forms clumps, sheds its leaves, and has spreading side branches.

Sources give garden heights of 2–5 feet [0.6–1.5 metres]. They report spreads of about 0.3–3 feet [0.1–0.9 metres]. Stems grow upright or bend to form arches. They range from light green to reddish brown. Fine white hairs grow in lines along the stems. The leaves are simple, with one blade each. They grow in turn along stems, with paler sides beneath. Most leaves are narrow and shaped like a lance. Those near the flowerheads are smaller than the rest. Larger leaves may have a few teeth near their tips. White hairs may line the main veins on leaf undersides.

Small flowerheads grow along side branches in loose, branched groups called panicles. Their rays are white or pale lavender, with yellow centres. The centres turn pink or violet as they age. Each flowerhead spans less than 0.08 feet [0.025 metres]. Most accounts say it blooms in late summer and autumn. Local records span July through November. Dry fruits called achenes form in autumn. Flowers draw butterflies and other insects that carry pollen. Birds also visit the plants.

Grow this aster in rich soil that drains well but stays moist. It grows in sun or part shade. Chicago advises part shade for this plant. Clay, loam, sand and chalk all suit it. It copes with acid, neutral and alkaline soil. Chicago says it cannot cope with drought. Give it moderate water; do not rely on dry conditions. North Carolina lists USDA zones 4–8. Chicago gives a smaller range of 5–7. The RHS gives it the UK hardiness rating H7. Plants reach full size in about two to five years.

Use it in borders, woodland gardens or groups beside paths. It suits wildlife gardens and gives flowers for cutting. It needs little care, though tall stems may need support. Split clumps in spring and keep strong young shoots. Cut old stems near ground level in late autumn. Pests may include aphids, mites, slugs, snails and eelworms. Diseases include Fusarium wilt and powdery mildew. Leaf spots and grey mould can also occur. The supplied evidence does not show whether this plant is safe to eat or toxic.