St. Johnswort
          Acceptable plant: St. Johnswort, also known as klamath weed, has a long history of herbal use. Recent research has suggested that it may be a valuable remedy for problems with nervousness. It is also used to treat a range of health problems from bladder trouble to cuts and bruises.

          Undesired weed: As a weed, St. Johnswort has dominated rangelands in Oregon, Washington, Idaho, and California. It is an aggressive competitor and forces out desirable wildlife and livestock forage plants. In some cases, this plant can be toxic to the animals that feed upon it.