Senna hebecarpa

American senna is a herbaceous perennial in the Fabaceae (pea) family native to moist forested areas and disturbed sites in eastern North America.  This is a striking plant while in bloom and has attractive foliage. The showy yellow flowers develop and grow into dark brown seedpods that attract birds and add winter interest to the garden.

American senna do well in partial to full sun, and moist to mesic conditions. A rich loamy soil is preferred, although sandy and rocky soils are also tolerated. It doesn't mind an occasional flooding. This plant can become quite tall when the soil is fertile and moist. It may flop over while the flowers and seedpods are developing. This plant is drought tolerant once established.  It is easy to propagate by seeds dropped by the plant or started in the early fall or by the division of roots in the early spring or fall. Plan to cut back mature seed heads in the late summer/early fall to control the number of plants in the garden. Full sun aids in better flowering.  

The American senna is a host plant for various Sulphur butterflies.  Before the butterflies emerge, foliage and flower buds are often eaten by the caterpillars. The seeds may be eaten by some upland gamebirds as well, particularly the Bobwhite. The plant has many medicinal uses.  In the 9th century, Arab physicians used to brew the leaves to make a cathartic (purgative) tea.  The leaves and seeds are used today as a laxative.  The Cherokee and other peoples use the root of the plant to treat high fevers, a worm remedy, treat fainting spells and to treat pneumonia.  

The American senna is most often found on riverbanks, in moist meadows, pastures, and roadsides. Some disturbance of the plant location is beneficial to allow it to grow without it being overtaken by other trees and shrubs. Occasionally, American senna is found in flower gardens because of its showy flowers.

Insects, Diseases, and Other Plant Problems:  Foliage and flower buds are often eaten by the caterpillars of the Cloudless Sulphur Butterfly.  Otherwise, they have no serious insect problems. Grown in rich soil it can flop over when flowering and may need support.