Crotalaria pumila is an annual or short-lived perennial that generally grows up to about 12 inches tall and about as wide or wider. It has alternate leaves with each leaf divided into three segments. The flowers are bright golden yellow with usually some red streaks, the streaks being especially pronounced on the back of the banner petal. Flowers are soon followed by inflated light brown pods with loose seeds that rattle when the pods are shaken. The plant does not spread vegetatively; however, the pods eventually split open with great suddenness and ballistically hurl the seeds several feet away from the parent plant.
The principal horticultural uses are as a small ornamental wildflower, as a low groundcover, and as a butterfly garden or insect garden plant. Two groups of insects are attracted to Crotalaria pumila: the foliage is used by the caterpillars of the cassius blue butterfly and the bella moth (a beautiful day-flying moth with white wings banded with orange-pink spots), while the flowers attract small native bees, which serve as the principal pollinators. Plants are very easily grown in any open, sunny spot with well-drained soil and the seeds germinate within a few days if the hard seed coat is lightly nicked or scratched between two sheets of sandpaper.
Crotalaria pumila: has a remarkably wide range that includes Florida as well as the western United States. It has also been reported from Maryland, and it has been introduced on the Hawaiian Islands. Outside of the United States, it occurs in both the Lesser and Greater Antilles and from Mexico south to Paraguay and Argentina.
Map courtesy of the United States Department of Agriculture Plants Database.
© 2010 Rufino Osorio (exclusive of the USDA map).