The Alabama Croton is a semi-evergreen woodland shrub found only in Bibb and Tuscaloosa Counties incentral Alabama. There, it grows in the dry, alkaline soils of bluffs bordering the Cahaba and Black Warrior Rivers, forming dense thickets known locally as “privet brakes.”
Alabama Croton This rare species was first discovered in July 1877. At that time, Alabama’s state geologist, Eugene Allen Smith, was conducting a study of the natural resources of Bibb County. On a dry bluff above the Cahaba River at Pratt’s Ferry (nine river miles upstream from Centreville), he collected a branch from an unusual shrub. He sent the specimen to Mobile pharmacist and botanist Charles Mohr, who was likewise puzzled and in turn forwarded it to the best-known southern botanist of that time, Alvan Wentworth Chapman of Apalachicola, Florida. Like Mohr, Chapman recognized the plant as a member of the Euphorbiaceae, or spurge, family owing to its distinctive floral characteristics and three-part fruits. Because it was new to science, Chapman named it Croton alabamensis in the second edition of his Flora of the Southern States.
Croton alabamensis is one of the rarest shrubs of North America. Although an outlying population was recently discovered in Texas, the Alabama Croton’s two main populations occupy limited areas on the limestone and shale bluffs above the Cahaba and Black Warrior Rivers. The shrubs, which reach between six to ten feet tall, produce very few leaves, with these being oval-shaped and two to four inches long. Alabama Crotons are most notable for the glistening silver scales that cover each leaf’s lower surface, reflecting sunlight and thereby reducing the plant’s heat load and enabling it to survive the extremely dry conditions of its habitat.
The Alabama Croton flowers during early spring (February or March), with separate male (staminate) and female (pistillate) flowers produced on the same branch. Successful pollination (mainly by bees) results in three-part, three-seeded fruits, also thickly covered by silver scales; the fruits pop open in early summer and catapult their seeds a short distance from the parent plant. The seeds remain dormant throughout the summer, fall, and winter and then germinate the following spring. In autumn, Alabama Croton leaves turn rosy red and golden yellow.
With their silvery undersides, Alabama Croton leaves are among the most attractive in the woods of central Alabama. Because of its brilliant fall foliage and ability to thrive on dry slopes, this native Alabama shrub recently has become a much-coveted garden plant. It is now in commercial cultivation and available to gardeners throughout the southeastern United States.
- Davenport, Lawrence J. “The Alabama Croton.” Alabama Heritage 33 (Summer 1994): 52, 54.
- Farmer, Joe A., and Joab L. Thomas. “Disjunction and endemism in Croton alabamensis.” Rhodora 71 (1969): 94-103.
- Ginzbarg, Steve. “A New Disjunct Variety of Croton alabamensis (Euphorbiaceae) from Texas.” Sida 15 (1992): 41-52.
- Wurdack, Kenneth J. “The Lectotypification and 19th Century History of Croton alabamensis (Euphorbiaceae s. s.).” Sida 22 (2006): 469-483.