I think I am going to have to change my mind on the Burgundy Belle. I've read that its mature spread is 30-45'. Thats almost as big as my whole yard. What do you think of the Cimmaron Ash?

These are all large-growing trees. If 35' is too much for you, look at recommended small trees. Utah Cooperative Extension Service may have suggestions for gardens in your state.

Even a large-growing tree like a red maple or a white ash will not grow 35' tall or wide overnight. It's a matter of balancing short-term desires against possible long-term results. To get an effect desired within the next 10 or 20 years it may in fact be necessary to plants a vigorous, large-growing tree - and "Damn the torpedoes!"

In a hot climate even if the house and lot are comparatively small a larger growing tree casting a substantial pool of shade might become a treasured feature in future.

Large-growing maples become dominating and competitive fairly early in life, making them unsuitable for serious underplanting on many sites. An oak would be a better choice for making a roof over a garden.

Pretty much all hardy trees concentrate fine roots just below the surface from the start. How suitable each kind is for making shade gardens is not a factor of what depth its roots are at. The idea that there are trees that do not root near the surface, leaving a completely root-free surface layer to plant or pave is a myth.

Shantung maple might work better.