Ageratina aromatica aka Lesser Snakeroot

Ageratina aromatica is a perennial in the aster family. Common names include lesser snakeroot and small-leaf white snakeroot. It is native to the eastern and southern United States. Its range reaches from Louisiana to Massachusetts, inland to Ohio. It grows along woodland edges, roadsides, fences, and field margins. It also grows in clearings and on land after fires. In North Carolina, it occurs most often near the coast and Piedmont.

Plants grow upright, reaching 2–3 feet (0.61–0.91 metres) tall. Their spread is 1–3 feet (0.30–0.91 metres). Growth is moderate, and the green flower stems are thin and hairy. The simple green leaves grow in opposite pairs. Their shape ranges from oval to narrow and pointed. Each leaf has a pointed tip and a wedge-shaped base. The edges have rounded teeth, though some have sharper teeth. Fine hairs cover both leaf surfaces. Leaves reach up to 3.5 inches (0.089 metres) long.

White flower heads bloom from August through October, sometimes into November. Each head holds 12–34 small, tube-shaped disc florets. There are no ray florets around the head. Hairy green bracts surround the base of each flower head. Bees and butterflies visit the blooms through late summer and fall. Brown fruits, called achenes, follow the flowers. Each has a tuft of white hairs. Wind carries the seeds away from the plant.

Grow this species in sun or light shade. It accepts clay, loam, sand, and shallow, rocky soils. Good drainage matters more than a single soil type. Acid to neutral soil suits it. Moisture-retaining soil works, but established plants also withstand drought. It grows in USDA hardiness zones 5–9 and needs little upkeep. Use it in borders, meadows, native gardens, or woodland edges. It also suits slopes and gardens made for pollinators. Seed is a recommended means of propagation. NC State reports no major pest or disease problems.

This plant has a history of use in herbal medicine. That history does not establish safe use. Plants For A Future notes an uncertain report of edible roots. Its lack of known hazards conflicts with NC State’s strong poison warning. NC State lists flowers, leaves, stems, and sap as poisonous. Eating the plant can cause severe illness or death. Reported effects include vomiting, weakness, heart damage, and coma. Milk from cows that ate it can also cause vomiting. Do not treat the tentative root report as evidence of safe food.