Saner, M. A., Clements, D. A., Hall, M. R., Dohan, D. J. and Crompton, C. W. 1995. The biology of Canadian weeds. 105. Linaria vulgaris Mill. Canadian Journal of Plant Science 75: 525-537.
Canadian: Occurs across Canada except in NU (Brouillet et al. 2016 Footnote 1 ).
Brouillet, L., Coursol, F., Favreau, M. and Anions, M. 2016. VASCAN, the database vascular plants of Canada, http://data.canadensys.net/vascan/ [2016, May 30].
Primary Noxious, Class 2 in the Canadian Weed Seeds Order, 2016 under the Seeds Act.
Cultivated fields, old fields, pastures, rangelands, shores, roadsides and disturbed areas (Saner et al. 1995 Footnote 4 , Darbyshire 2003 Footnote 5 ). In Canada, it is a problem in pastures and crops such as wheat, barley, oats, canola and peas (Saner et al. 1995 Footnote 4 , CABI 2016 Footnote 3 ).
Worldwide: Native to Europe and temperate Asia (USDA -ARS 2016 Footnote 2 ) and introduced in North America, Chile, South Africa, Australia and New Zealand (CABI 2016 Footnote 3 ).
Yellow toadflax was once grown as an ornamental, dye and medicinal plant (Saner et al. 1995 Footnote 4 ). This species first appeared in Ontario and Quebec at the end of the 19th century and moved into the Prairie Provinces after 1920, through contaminated alfalfa seed and as a garden plant (Saner et al. 1995 Footnote 4 ). Yellow toadflax is a prolific seed producer and reproduces from both seed and clonal propagation (Saner et al. 1995 Footnote 4 ).
Closely related to moss roses, purslane has fleshy succulent leaves and stems that hug the ground, radiating out from a single taproot. It has small yellow flowers and can produce large mats in bare soil. Purslane seeds germinate best when soil temperatures reach 90 degrees or more, so a preemergent herbicide applied in April will likely have lost its efficacy by June when purslane starts growing. Pull by hand, making sure to remove all parts of the plant. Seed bare spots in the lawn in spring or fall to prevent purslane from gaining a foothold in these areas.
• Dig only when necessary. Thousands of weed seeds sit just below the surface of the soil, waiting to be kissed by the sun. The more you disrupt soil in your beds and lawn, the more you increase the likelihood that seeds will germinate.
Producing 150,000 seeds per plant, crabgrass is tough and determined to take over. This annual grass pops up frequently around heat-absorbing areas like driveways and sidewalks where soil warms faster, triggering the germination of crabgrass seeds. Though hand-pulling is helpful, it’s unlikely that you’ll be able to control the spread using just this method. Your best defense is a preemergent herbicide, or crabgrass preventer, applied in early spring before seeds have a chance to germinate.
Also called wood sorrel, oxalis is a perennial weed that looks a lot like clover, except with yellow flowers. It forms a dense, low-growing mound that spreads by seed, stem fragment, or underground root. Hand-pulling rarely works because you leave much of the plant behind. Your best bet for small areas is digging by hand, but this option often takes several seasons to have an impact. Apply a broadleaf herbicide like dicamba to actively growing plants before they set seed. As with all chemical treatments, follow the application instructions and wear protective clothing.
• Pull weeds when soil is damp. Hard soil is reluctant to release weeds. Wait a day or two after rainfall to do some hand-pulling or digging.
Perennial that grows 8 to 31 inches tall from creeping roots, often forming colonies. Plants are light green and have yellow flowers with orange throats and bloom during the summer (June to September). It has a bad smell.
Leaves are alternately arranged and numerous along the stem. Each leaf is very narrow (linear) and up to 3.9 inches (10 cm) long. They are hairless and have pointed tips.
Yellow toadflax is found in a variety of habitats including roadsides, edges of fields, rangelands, meadows, cultivated fields and wastelands. Please click here to see a county level distribution map of yellow toadflax in Washington.
Yellow toadflax can reproduce by seeds and by its horizontal rootstalks which send up new shoots.
Flowers form a cylindrical capsule that is about .4 inches long. Seeds are dark in color, brown to black, and are flattened, having a papery wing.