Ageratina aromatica, also known as lesser snakeroot and small-leaved white snakeroot, is a North American species of plants in the family Asteraceae. It is widespread and common across much of the eastern and southern United States from Louisiana to Massachusetts, as far inland as Kentucky and Ohio.
Ageratina is derived from Greek meaning 'un-aging', in reference to the flowers keeping their color for a long time. This name was used by Dioscorides for a number of different plants.
The lesser snakeroot lives in woodlands as a perennial in early successional gap habitats created by fires or fallen trees. It is often found near rocky outcroppings.
Ageratina aromatica is insect pollinated and is recorded to have been visited in northern Florida by the bee species Agapostemon splendens, Augochloropsis metallica, Augochloropsis sumptuosa, Bombus bimaculatus, Hylaeus floridanus, and Lasioglossum apopkense.
A. aromatica is listed as endangered in New York.
A variety incisum from Florida and Virginia has been described.