It blooms in the summer with yellow flowers, followed by long seed pods, and can grow up to 2 m (6 ft) tall.

Senna marilandica has green, round, unbranched stems rising from a shallow, fibrous root system, reaching a height of about 2 m (6 ft).

[5] The inflorescences are racemes of six to nine yellow flowers, appearing both from the leaf axils (axillary) and at the end of the stems (terminal).

[6][7] After the flowers are fertilized, drooping pea-like seed pods, up to 8 cm (3 in) long, appear.

[5] S. marilandica is native in the United States from Nebraska to the west, Florida and Texas to the south, Wisconsin to the north, and New York to the east.