Oxeye daisy (Chrysanthemum leucanthemum) is a perennial that spreads both by seed and shallow creeping roots. It was introduced from Europe in the early 1800s as a grass seed contaminant and as an ornamental flower. Shasta daisy is a sterile cultivar of oxeye daisy; however, it can both revert to become fertile, as well as cross-breed with oxeye daisy to produce an invasive hybrid. If your Shasta daisy begins to spread by seed or roots, it has reverted to its invasive counterpart and should be removed.
Stems are erect, smooth and unbranched. Oxeye daisy can grow as tall as 1m but usually reaches only 30-60cm in height.
Leaf appearance is one of the methods to tell oxeye daisy from Shasta daisy. Oxeye daisy has basal leaves that are spoon-shaped with scalloped edges, while Shasta daisy basal leaves are long, thin and lance-shaped with almost smooth edges.
Flowers and Fruit
Oxeye daisy has a typical large white daisy flower. Each plant can produce up to 500 small black seeds that can germinate immediately upon dispersal, or remain viable in the soil for up to 3 years.
Oxeye daisy flourishes in nutrient-poor soils, as well as at higher elevations, up to 1000m. It prefers full sun but will tolerate partial shade as well. In urban settings, it will spread quickly through flower gardens and into lawns, growing as a groundcover under the level of mowing.
Oxeye daisy has established itself very successfully in urban environments as a low maintenance ornamental flower. From flowerbeds, it spreads across lawns into easements and parks via creeping roots. In pasture situations, it is not favoured by livestock, and plants consumed by dairy cattle may taint the milk with an off-flavour.
The easiest way to prevent oxeye daisy from becoming a problem in your yard is to never plant any white-flowered daisies. There are many other ornamental daisies of different colours that are non-invasive and won't escape into your lawn. Immediately remove any white-flowering daisies that you find. Oxeye daisy is also a popular component of wildflower mixtures; however, there are no native white-flowering daisies in Alberta, so it is immediately conspicuous as a non-native wildflower. Never purchase wildflower seed mixtures that do not list all species on the label.
Because of its shallow root system, oxeye daisy can be eradicated through repeated intensive cultivation. Hand-pulling or digging out plants can be effective so long as all root pieces are removed. Repeated removal will be required to starve the roots and kill the plant.
Oxeye daisy's waxy leaves easily shed herbicide; however, control may be achieved using products like glyphosate or 2,4-D applied at the proper growth stage and rate. Consult your local Agricultural Fieldman for more information.