Definition of Canada thistle in English:

Canada thistle

Pronunciation /ˈkanədə ˈTHisəl/ /ˈkænədə ˈθɪsəl/

noun

North American
  • The European creeping or field thistle, which has become naturalized as a serious weed in North America.

    Cirsium arvense, family Compositae

    ‘Occasionally, broadleaf weeds, such as Canada thistle or ragweed, become established in winter wheat fields and interfere with grain harvest or with the following soybean crop.’
    • ‘Fields with quackgrass, Canada thistle, and other cool-season perennial weeds will almost always require the use of glyphosate around the time of planting.’
    • ‘As agriculture expanded onto the prairies, wild oats and sow thistle, leafy spurge and Canada thistle migrated westward.’
    • ‘Under growth-chamber conditions, mite populations on a Canada thistle plant can reach very high levels, causing severe damage to the plant.’
    • ‘Perennial grasses such as bluegrass and quackgrass and broadleaves such as Canada thistle, bindweed, and curly dock also could be addressed with the weed control program.’
    • ‘Tillage with a chisel plow, disk, or field cultivator may actually help spread perennials with creeping root systems, such as Canada thistle and hemp dogbane.’
    • ‘Perennials such as Canada thistle, hoary vervain, ironweed, goldenrod, and curly dock generally respond better to fall applications when the plant energy reserves are translocated down to the roots.’
    • ‘Avoid tilling overly aggressive or invasive plants that produce root-buds, such as crabgrass, johnsongrass, bindweed or Canada thistle.’
    • ‘In particular, perennial broadleafs and grasses such as dandelion, curly dock, Canada thistle, and quackgrass are much easier to manage prior to planting a forage crop.’
    • ‘Herbaceous perennials, such as quackgrass, mugwort, and Canada thistle, die back to the ground each year.’
    • ‘The weeds that appear above the wheat canopy late in the season, such as ragweeds and Canada thistle, can often be easily controlled with a spring herbicide treatment.’
    • ‘Smartweed often grows in potassium-poor soil, while Canada thistle suggests low magnesium levels.’
    • ‘The larvae of the painted lady butterfly - the thistle caterpillar - have been drawing a large amount of attention from anyone who has observed Canada thistle patches this spring.’
    • ‘A search is under way for viral-infected Canada thistle plants in the areas where they were once reported - Denmark, England, and North Dakota.’