Hi! I was going to plant a few buddleias davidii (butterfly bush) on the chicken meadow to give them better cover from sun and hawks but just now read that they are invasive here and not a safe choice if you are close to nature preserves which we are. Argh. I don't know if they are actually illegal, so I am not actually completely against getting them, yet, but I wonder what would be good alternatives? I am looking for something that gets big and has a wide canopy with low hanging branches for the chickens to hide under. Thanks!