References in periodicals archive ?
Covering with paper: Quackgrass and Canada thistles in patches not over two rods square can sometimes be economically killed by cutting the weeds close to the ground just when in bloom and covering with tar or some other heavy building paper.
Growing alfalfa: Canada thistles have been completely eradicated where good stands of alfalfa were secured and maintained for three years or more.
Like quackgrass the Canada thistle is a perennial plant.

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