The wall isn't a good idea, you're right, the tree roots will eventually move it. Besides, you might cut into some roots that could harm the tree.

Don't backfill either. You potentially could smother out some of the feeder roots.

If it were me, I would push for a shade garden and a simple edging around the landscaped area. Hostas do very well under trees, especially maples.

 

I agree with white gardens, however if the roots are exposed, lay some top soil just a thin layer and cover with mulch and then go with hostas, or i don't know too much about your area, but find a deep shaded plant, BUT also consider the amount of water that tree will be taking away from the plants. I say go with the hostas

 

You are planning on wounding this tree by cutting roots, then building a 3' tall wall on top of the fresh wounds, and THEN backfilling the area up to the tree with soil? This tree will be dead in 2-3 years if you do this.

The exposed roots are most commonly from over watering, i.e. sprinkler systems, or planted too deep/too much mulch. The tree sends the roots up instead of down throught he soil looking for oxygen, water, and nutrients.

If you snap some pics I am sure we can help with a better plan than killing the tree

 

thanks i will take some pics and post them

 

You are planning on wounding this tree by cutting roots, then building a 3' tall wall on top of the fresh wounds, and THEN backfilling the area up to the tree with soil? This tree will be dead in 2-3 years if you do this.

The exposed roots are most commonly from over watering, i.e. sprinkler systems, or planted too deep/too much mulch. The tree sends the roots up instead of down throught he soil looking for oxygen, water, and nutrients.

If you snap some pics I am sure we can help with a better plan than killing the tree

It might take longer than 2 or 3 years, but the tree will certainly be a goner if you proceed as described in your initial post. There are many (comparatively) short shade plants that will look great under a tree. I'm particularly fond of Lamium (deadnettle). If you mix the white flowered with the pink flowered, it looks especially nice.

 

You are planning on wounding this tree by cutting roots, then building a 3' tall wall on top of the fresh wounds, and THEN backfilling the area up to the tree with soil? This tree will be dead in 2-3 years if you do this.

The exposed roots are most commonly from over watering, i.e. sprinkler systems, or planted too deep/too much mulch. The tree sends the roots up instead of down throught he soil looking for oxygen, water, and nutrients.

If you snap some pics I am sure we can help with a better plan than killing the tree

Boston, I agree totally. I know you're a tree guy, I Have a Swamp Maple at my own house. Everything I have been told, is this type of tree naturally has surface roots. Is this not true?