I used to pass by a farm set back from the road, which had a big tree obviously used to mark the entrance from the highway. The grass never seemed to get too tall under the shade of the tree, the snow never too deep. What made it so remarkable is that the people painted
old equipment from around the yard and hung it from the tree branches.What you would see then was rather magical - purple cog wheels, lime green motor belts, yellow circular saw blades, rainbow chimes of broken tool handles, anything as long as it had cheery colour and could swing with the wind. It got to be a game to see what they added next.

I like the direction Adrienne is taking with this, and your idea of a rock. If you do an internet search for renegade gardener you'll find some arguments against giving a tree a little tutu of plants. I think you might think of giving it company with something of a reasonable scale, so it's not an isolated element, and think beyond plants at its base. Maybe a family of old painted bicycles or rusted out big antique farm equipment - tractor, plow, etc? Or if you're not into that look, a big bench or two with that rock? Something that reflects you and your interests.

KarinL

Are you really in zone 2? This may not be useful, but ...

An old farm near us has a big tree and they put a ring of orange daylilies around it. Nothing exotic, just the old ditch lilies or privy lilies. It has a nice shape & because it's probably 2-3" wide they drape well. I imagine you could slide a mower deck just under the draping foliage to trim the grass without killing the plants.

But I don't think they are hardy to zone 2.

Yes I am really in Zone 2, not as frigid as it sounds. We have some beautiful gardens up here believe it or not. I grow a lot of plants rated zone 4 or zone 5. Plants are a lot tougher than nurseries seem to think. We get piles of snow, and I mulch so most plants make the winter with flying colors. Im not really into the old machinery look,I have seen old wagons, but they are usually filled with flowers, so that means high maintenance, but like the idea of a bench and we have an abundance of big rocks. Does any one have some pictures? Open to any ideas, I would like to get creative with this area, but keep any plantings, to plants that can survive without irrigation.