Centers of diversity for Achillea are in Europe and Asia. Achillea ageratum, A. distans, and A. ligustica have been reported as occurring in North America. Labels on herbarium specimens examined indicated that those reports were based on cultivated plants; there is no evidence that any of the three has become established in our flora. Achillea filipendulina may be persistent or established in California (F. Hrusa et al. 2002) and in Michigan (E. Voss 1972–1996, vol. 3).