From John B. Boyle and Evelyn W. Moyle's Northland Wildflowers

Bouncing Bet (Saponaria officinalis) Description A European perennial that escaped from pioneer gardens to nearby roadsides. The showy clusters of pink flowers top leafy stems that are commonly 1 to 2 feet tall. Occasionally there are plants with semidouble flowers that range in color from white to rosy lilac. The plant, especially the rootstock, contains saponin, which produces slippery suds in water. Late spring, summer Habitat and Range Widely naturalized in Minnesota and elsewhere in temperate North America. Comments It was once used as a natural detergent for washing fine fabrics and is still used occasionally in museums for cleaning old tapestries. It makes a showy garden perennial but is aggressive and spreading.
White Snakeroot
Purple Coneflower