What can I do with an area under trees that inhibits grass growth?

Plant hosta lillies, coleus, mulch & put in some edging and forget about the grass.

Hi, Rita: If you don't want to try to dig with large roots, just pick a ground cover! There is plenty of choice depending on where you live. We have successfully used Asian Jasmine. We live in North Texas. Good luck!

Rita: I am a big fan of caladiums. ...they come in a variety of colors too!

My parents had the same issue and put a rock garden under the tree. They planted some sedums between some of the rocks and it looks really nice.

Have you considered ground covers.

They might appeal to you and they work wonderfully under trees.

I am using vinca and pachysandra in my zone 7.

Hosta could be another alternative but the deer love them. I have to rethink hosta there after they got ravaged by deer or bunnies.