Hi all.

I've let a Forsythia in the back yard grow without pruning for some ten
years now.

I'd like to bring it under control.

I think I can figure out how to prune it back, and let it recover next
spring. What I don't know is how to get rid of the secondary roots. It has
arched over and rooted itself in areas that I want to return to lawn. Do I
have to dig up the roots? How deep do I have to dig?

I know almost nothing about gardening.