Hello madformaples,

I'm a general tree forum fella not a maple fella but I'll give my advice since I'm first.

By ledge do you mean sharply defined underground rock group?

Unless there is a PH issue with the soil over the rocks I'd go ahead and plant it. Sharps Pygmy is a small growing tree (with excellent fall color!). My theory is all them trees grow on the rock ledges along the highways.

Now if there is another better place and the Sharps is a $200 investment I might reconsider. But if that's the place it seems a small tree is the choice.

Thank you Toronado. I decided to plant it there, but to attempt to break up some of the ledge (it looked like shale to me) with a maul that i had. Sure enough it broke up pretty easily, giving me enough room to get comfortable.

My Sharps Pygmy is looking happy so far and i love the look it gives my small garden :)