To tease wool, or to card it, was to use the teasle, or a card, to prepare it for spinning.
"Minor Poems by Milton"
John Milton
One may see a large slice taken from a field by elecampane, or by teasle or milkweed; whole acres given up to whiteweed, goldenrod, wild carrots, or the ox-eye daisy; meadows overrun with bear-weed, and sheep pastures nearly ruined by St. John's-wort or the Canada thistle.
"A Year in the Fields"
John Burroughs