Can anyone suggest some options? I'm looking for a low-cost, shallow-rooted ground cover plant that provides dense shade, for planting around tree saplings. This would be to (a) stifle weeds, and (b) provide shade and shelter for frogs. Something that doesn't send runners everywhere would be ideal, though I don't mind if it spreads in an easily-controllable way. Something that keeps its leaves year-round would be ideal. If it also adds nitrogen to the soil, that would be an excellent bonus.

Many thanks!

Al_w