White snakeroot has opposite leaves which tend to be flat at the base, have regularly serrated edges, and come to a point. The plant tends to have an orderly, symmetric form, often branching and forming a relatively thick shape, but its leaves frequently show evidence of insect damage, both trails from leaf borers, and chunks taken out of the leaf by larger insects.
It grows to 3 feet tall under ideal conditions, but is often shorter.
The flowers are white, in small clusters near the end of each stem. A given plant will typically branch, and bloom in several clusters. Flowers appear in late summer to fall, with a few plants occasionally starting to bloom mid-summer. The flowers are followed by seedheads with wind-dispersed seeds.
This plant looks similar to plants of the Eupatorium genus, which go by the common name of "Boneset". White snakeroot used to be placed in this genus. These plants are still close relatives, but are now classified in a separate genus. Another close relative is the blue mist flower, Conoclinium coelestinum, which looks similar but blooms blue, and is slightly harder to grow, needing more consistent moisture.