Plant Profile: Senna marilandica - Wild Senna
Updated: Aug 17, 2022
In late summer and early fall many of the large, architectural, yellow blooming plants in the landscape are robust members of the composite family, and some view the redundancy of form with a jaundiced eye. If this strikes a resonant cord with you, consider Senna (Cassia) marilandica, AKA Wild Senna. A member of the pea family, this plant sports handsome blue-green foliage of compound leaves, supplying a welcome contrast of texture. July into September, racemes of yellow, pea-like flower clusters bloom atop un-branched stems, giving way to black, 4” pea-like seed pods in the fall.
Wild Senna flowers attract bumblebees and other pollinators, while the foliage and flowers are food for the Larva of a number of butterflies, skippers, and moths. However, the foliage is somewhat toxic and cathartic, and thus is usually avoided by White-Tailed Deer and other mammalian herbivores.
The properties that make the foliage distasteful to mammals result from phytochemicals that give this plant a prominent place in herbal lore. Medicinal usage ranges from a digestive aid for irritable bowel, to diuretic, cathartic, and vermifuge applications. Infusions have been used to treat fevers and heart problems, while a poltice of the root has been used for treating sores, soaked seeds for sore throats.
Wild Senna is easily grown, reaching 4 to 6 feet tall and spreading 2 to 3 feet wide. Tolerant of heat and humidity, it grows best in medium moisture, well-drained sandy or clay soils in full sun.