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Buffalobur (Solanum rostratum)
ODA rating: B
Oregon buffalobur distribution
Other common names: Kansas thistle, Texas thistle, and Colorado bur
Click on photo below to view larger image.
Image courtesy of Rich Old, XID Services

Image courtesy of Tom Forney, ODA

Image courtesy of Tom Forney, ODA.
If images are downloaded and used from the ODA web site please be sure to credit the photographer.
Annual; flowers midsummer to September.  Grows up to two feet high.  The stems, leaves, and even flowers sport many sharp spines.  Leaves are deeply lobed and grow up to 5 inches long.  Yellow flowers are one inch across with five petals.  A dry berry covered with sharp spines contains numerous black, wrinkled and flattened seeds. 
Buffalobur is a native of the Great Plains and is drought tolerant.  It can be found in meadows, dry rangeland, pastures, lawns, cultivated fields, roadsides, and waste areas. It is not very competitive and survives in disturbed, dry areas. It can grow in a wide variety of environmental conditions and serves as a host for the Colorado potato beetle.  The burs may cause damage and considerable loss in wool and fiber value for sheep and goats.
Buffalobur is a native North American species that's range extends from central Mexico northward across the Great Plains.  The name "buffalobur" dates back to the settlement of the Great Plains when the plant grew abundantly in the disturbed soil of bufallo wallows.  It is thought buffalo carried the burs great distances in their shaggy coats.
Distribution in Oregon:

Biological controls
No approved biological control agents are available.