Just as not all unwanted plants are noxious weeds, not all noxious weeds appear to be problematic exotics. Some invasive plants may be considered pleasant in appearance with brightly colored flowers that resemble native wildflowers and garden ornamentals. Many of our most problematic weeds arrived intentionally with early colonists and pioneers to be planted as food, medicinal and decorative components of homesteads and gardens. Others were unintentionally introduced through contaminated seed, imported products, and vectors of spread such as vehicles. The State of Montana has designated 36 plants as noxious weeds due to their negative impacts on our state’s ecosystem productivity and biodiversity, and the vitality of native species including wildlife and aquatics. Leucanthemum vulgare, commonly known as the ox-eye daisy, is a flowering plant native to Europe and the temperate regions of Asia introduced to North America as an ornamental and incidentally as a contaminant of imported hay and grain seeds in the 1800s. This plant is a great example of a noxious weed that looks (at first glance) like an unoffending wildflower. Ox-eye daisy can be found across the Clark Fork, Clearwater, and Blackfoot river watersheds in concentrated populations that have been rapidly increasing in density and distribution. A member of the Aster family, each flower head is a composite of tiny yellow disc florets in the center surrounded by white petal-like ray florets, creating a classic daisy-like appearance. Thin 1- to 3-foot-tall stems can branch to produce multiple flower heads and upwards of 200 seeds. Seeds are wind dispersed and ox-eye daisies also spread vegetatively via rhizomes. Dense stands along roadsides and waterways and in pastures and meadows outcompete native flora reducing biodiversity and degrading pasture quality. Ox-eye daisy is also known to be a host or carrier for several species of gall-forming nematodes that feed on crops. Because ox-eye daisy is often perceived as a showy, pretty plant, proper management is often neglected. Education and awareness, prevention practices, and a combination of control methods are important components of an effective management approach.
To learn more about identifying native and non-native plants, feel free to reach out to Vegetation Coordinator Karen Laitala at karen@blackfootchallenge.org.