Saint John'swort
Hypericum perforatum
Description
Also called Klamath weed. Height to 5 ft., usually closer to 2 ft. Five-petaled yellow flowers with black dots; flowers June to August. Leaves are oblong and have translucent dots.
Habitat
Occurs in fields, forest edges, and pastures; sunny areas that are well-drained, prefers sandy soils.
Location in Nebraska
Fairly widespread throughout Nebraska.
Pathway of Introduction and Spread
Originally from Europe for landscape use, but has escaped into natural areas. Used as a remedy for depression. Seeds spread by animals, wind, and water; colonizes by rhizomes and stolons.
Impacts
A single plant can produce 15,000-30,000 seeds; Forms dense colonies and can be toxic to livestock. Competes with native vegetation.
Photo Credits:
“Weeds of the Great Plains” – Nebraska Department of Agriculture