Does anyone know how far underground this can travel? Is it shallow rooted so that a barrier of, say 10" can be put in place to contain it or will it go deep to get under one?

I have a few spots where I might welcome it's spready-ness, but I don't want it to turn into a fight like I have with my (inherited with the house) lily of the valley.

One is a dry semi shaded area under spruce trees bordered by mowed lawn and 2 car wide driveway. On the other side of the driveway is a mixed perennial bed so I want to be sure it won't escape into that bed. I already have another mixed bed invaded by lily of the valley to tend to so I don't need another battle, lol.

The other is a steep slope, semi shaded, heavy clay. JUST replanted. Mixed in are lily of the valley (it's welcome to spread here), ditch lilies, showy evening primrose and crown vetch. This area needs erosion control. There is a wildflower garden to one side of this on a flat area, but if it gets taken over and the erosion control is successful I can deal with it. This is then surrounded by mowed lawn, with another wildflower garden about 20-30' away with the mowed lawn between.

I've seen mention of it doing well on a steep slope, we also have a bluff face with is nearly verticle but has a very slight slope to it where I might try it out if I can get ahold of some clumps cheap enough. We're going to try ivy there (it's north facing so quite shady) but anything that works is fine by me!