FEIS: DISTRIBUTION AND OCCURRENCE: "Spotted knapweed is native to eastern Europe, though it now occurs in western and central Europe. It was introduced to North America, probably as a contaminant in alfalfa (Medicago sativa) seed and/or ship's ballast, in the late 1800s ... . In 1920, the distribution of spotted knapweed in North America was limited to the San Juan Islands, Washington."
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 05/03/2025).
one or more occurrences