Larkspur volunteers are pretty easy to identify in the garden I think. Unlike big ugly broadleaf weeds, their foliage is lacy and pretty.
Your best bet to establish larkspur is to get a bunch of seeds and direct sow in late summer/early fall. (Probably around Sept first for most folks). They sprout and grow, remaining green all winter
What looks like green groundcover on this round bed is actually larkspur volunteers in one of my beds in January 2010.
Karen
