hi:

I am thinking of setting up a wildflower garden in my backyard using black
eyed susan and purple coneflower. I plan on starting small and maybe work
may way up to 1/4 or 1/2 of an acre. My concern is that they will end up
propogating onto my neighbors lawn or onto parts of my backyard that i want
to stay as a lawn. Will i have trouble stoping these aggressive wildflowers
from propogating or will mowing be enough to control them?

thanks