Weed of the Week: Coffee Senna

Written by: Blake Edwards, Tom Eubank and Jason Bond

Coffee Senna

Family: Caesalpinia

Scientific name: Senna occidentalis

Synonyms: Bricho, Coffeeweed, Septicweed

Coffee senna is an erect, summer annual plant that has alternate and compound leaves along the stem with opposite leaflets.  Coffee senna is easily confused with sicklepod (Senna obtusifolia) but can be distinguished by several distinct characteristics.  A spherical gland is present on the base of the petiole of coffee senna.  Coffee senna has pointed leaves, while sicklepod exhibits more of a round leaf shape.  In addition to coffee senna having pointed leaves, it does not extrude an odor like sicklepod when the leaves or stem are crushed.

Coffee senna, which is native to the tropics, prefers environments comparable to southern Mississippi.  Although this weed is not frequently found in the mid to northern region of the state, it is dispersed to some extent across the southeastern U.S.  In regions such as southern Mississippi, coffee senna can be problematic in pastures.  Problems arise due to the toxins that this weed, as well as sicklepod, exudes.  This toxin is known to cause digestive tract irritation and cardiac muscle degradation, which may warrant a control program.

Bryson, C.T. and M.S. DeFelice. 2009. Weeds of the South. Athens, GA: University of Georgia Press. pp. 207

Photo courtesy of http://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/weeds/Media/Html/images/Senna_occidentalis_(Coffee_Senna)/senna_occidentalis5_-_CG.jpg