Deadhead as soon as their done flowering. They can reseed very heavily.

They do seed in, but they also spread by runners. If it were me, I would not mind them spreading into the shrubs. They just are a nice groundcover under them. The lawn is different. If you like pure grass, the lamb's ears are pretty easy to pull back. Once in late spring and once in late summer should do it. If you're not worried about pure grass, the lambs ears are amenable to mowing. They end up being lowgrowing patches of silvery leavesamong the grass.