This summer, you may have noticed what looks like a large dandelion plant covered in blisters growing in your lawn or landscape. It's known as bristly oxtongue, and if you examine or touch it you'll see and feel why. The stems and flower bracts are bristly, and the leaves are covered with blisterlike swellings that are prickly to the touch.
Mature plant of bristly oxtongue. (Credit: Larry L. Strand)
Bristly oxtongue can be an annual weed or a biennial weed. It thrives during the winter and warm weather and can grow to be over 3 feet tall. This weed spreads by seed, which can be dispersed long distances by the wind.
According to the book, Pests of the Garden and Small Farm, you can control bristly oxtongue by removing rosettes by hand before stalks develop. Read more about this weed on the bristly oxtongue page in the UC IPM Weed Gallery.
Not sure if the weed you are seeing is bristly oxtongue? Visit UC IPM's weed identification key or see photos and features of other weeds in the Weed Photo Gallery.