- Sisymbrium altissimum is an annual/biennial herb native to Eurasia. Plants can reach almost 5 ft. (1.5 m) in height.
- Cauline (stem) leaves are alternate, 0.5-5 in. (1.3-12.7 cm) long and decrease in size up the stem.
- Flowering occurs in late spring to summer, when small, 4-petaled, yellow to white flowers develop in groups at the apex of the stems.
- Fruits are narrow seed pods that are 2-4 in. (5-10 cm) long and contain more than 120 seeds.
- Ecological Threat
- Sisymbrium altissimum was first seen in the United States in 1878 in Philadelphia; seeds were probably introduced accidentally in ship ballast. Plants invade fields, open forests, and other disturbed open areas.
Howard, Janet L. 2003. Sisymbrium altissimum, Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory 
University of California, Jepson Flora Project 
Flora of North America, www.eFloras.org 
USDA NRCS PLANTS 
USDA ARS GRIN 
Images from Bugwood.org