Lady a few doors down from me had her CRAP APPLE tree removed last fall down to the stump. Now she has "FLOWERING Crap Apple " coming up all over her lawn in an area about 30 feet around the stump. What can she use to kill off these without killing off all the grass in the area? They are growing back in at a rate of about 6-8" a week after cutting the lawn. Located in Ontario Canada. Thanks for any help.