Canada thistle

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Canada thistle:

see thistlethistle,
popular name for many spiny and usually weedy plants, but especially applied to members of the family Asteraceae (aster family) that have spiny leaves and often showy heads of purple, rose, white, or yellow flowers followed by thistledown seeds (a favorite food of the
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References in periodicals archive ?
The way or Canada thistle is often ignored and pathways are
Examples include quackgrass and Johnson grass (both have rhizomes); leafy spurge and Canada thistle (both have creeping roots); and bermuda grass (has stolons).
Field evaluations were conducted to determine the glyphosate tolerance of Roseau and to develop the appropriate management strategies for controlling Canada thistle in seed production fields.
Canada thistle, one of the most tenacious weeds in the world, proved the most susceptible; the 5-percent concentration had a 100-percent kill rate of the perennial's top growth.
Under growth- chamber conditions, mite populations on a Canada thistle can reach very high levels, causing severe damage to the plant," he notes.
On the Control field the percentage of plots with quack grass and wild carrot increased by 5% and 10%, respectively, between 1998 and 1999, while the percentage of plots with Canada thistle (Cirsium arvense) decreased by 17% of plots.
One of the hardiest weeds is Canada thistle, a perennial found throughout North America.
It will safely control poison ivy, poison oak, Canada thistle, star thistle, smart weed, quack grass, horsenestle and almost countless other noxious weeds without harming anything except weeds.
The aggressive invasions of both leafy spurge and Canada thistle into Theodore Roosevelt National Park (THRO) have gained much attention because of their ability to severely degrade large areas of land and displace native flora.
Certified birdsfoot trefoil seed production is limited by severe infestations of Canada thistle [Cirsium arvense (L.

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