[M. Ready]

Is there anyway to keep perennials from coming back up without digging them all up?

One of the previous owners of my house planted the damn things all over the place and in random spots. They did the same thing with the trees, 10 different kinds of trees planted in random places.

 

[Bob Mariani]

Just cut back the painted parts, these plants will return. To kill them make a cut at the base and pour in agricultural salt, which the plant will draw into the roots and kill the plant.