Where do you live?

What kind of trees? Will they be pruned up to a high canopy or a low canopy?

Kind of amazing that a smartass has not yet shown up to answer "orchard grass!"

I was waiting until I got the basic answers out of the way to suggest orchard grass. When I was a kid in SoCal we had orange groves all around us. One grower sprayed diesel fuel to keep the weeds down. Another one encouraged nutgrass to grow up by watering too frequently. The one with the nutgrass had the side benefit of discouraging us kids from running through, picking the oranges, and throwing them at each other. We gravitated to the one that smelled like diesel fuel because we could run faster on the hard surface.

There is an orchard owner in my area (somewhere) who piles mulch between the trees. I have seen the pictures, but don't know much more than that. There were several feet of mulch. He claims that he never has to irrigate because the mulch holds all the moisture down.

I live in Idaho.

I plan to plant fruit trees that will grow in our cold climate (apples, cherries, pears, apricots)

I'm not a pruning expert, but the trees will be fairly standard.

Sorry. I got tied up and didn't get a chance to respond. I want to have a soft green ground cover, but I don't want it to get too tall. I'm currently thinking that I'll kill the weeds, till it up, and plant Hard Fescue grass before I start planting fruit trees.