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Plant of the Month

September 2018 Plant of the Month

Helianthus decapetalus L., Thin leaf Sunflower

The September  Plant of the Month is a native composite in a genus characterized by large, showy flowers.  Thin leaf is a widespread sunflower, occupying moist rich soils on the Inner Coastal Plain and throughout the Piedmont, Highlands, and Valley and Ridge regions.  Mary Hough (1983) shows its range excluding most of the Outer Coastal Plain.  Regionally, it is found from the Carolinas to Maine, west to Wisconsin.

The plants are identified by large, rough textured, deltoid leaves, on relatively thin stems that can grow in excess of 2 meters.  The flowers are pale yellow and the petals, many times 10, are widespread.  The leaves have coarse teeth, and three main veins.  The sunflowers are an upland species that prefers rich moist loams over sandier textured soils.

Native Americans across the continent used members of the genus Helianthus for food, fiber and medicine.  Thin leaf sunflower is known to be used as skin aid  Macerated rooted is applied to sores of long standing (Moerman, 1999).  It seed was large enough to be harvested as were many wild plants were during the archaic and woodland periods.  There is no written record of this use in the historic documentations, and the region’s acidic soils are not good for organic preservation, so this is a probability we may never resolve.

JRA, 9/2018


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