Many people manage their clay soil without excavating their whole property, so hold on, it won't be as bad as all that. The trees and shrubs are more likely to be dying due to drowning than to being root bound. There are methods of planting that will be helpful to you. See the link below, it provides really good planting information from the U of M Extention Service (your best friend for advice about yard and garden matters in MN) If you further explore the site, you can find information about which trees, shrubs and perennials are best suited to your clay soil type. Success in gardening is usually increased when you match the plant to the situation rather than trying to match the situation to the plant (you will have better success over the long run and it will be less expensive). I am sure othes will have experiences to share with you as well, but this is a really good place to start. Good Luck...it may not be easy but it is possible and not nearly as bad as you think. Helen.

Here is a link that might be useful: planting in clay soil

Most trees and shrubs that do well in wet areas also do well in drier, compacted soils that you have. This is because wet soils also have a relative lack of oxygen in soil due to excess moisture, just as compacted clay does due to compaction. I don't know why a couple of your arborvitae croaked, but they should do fine. Other good choices: Tamarack or other larch trees, alders, willows, white or Black Hills spruce(not Colorado spruce),dogwood shrubs and viburnum shrubs. While you might think River birch would be a good choice, the pH of your subsoil clay will be too high, and cause chlorosis on birch.

Your planting is paramount. Adjust your new materials at or above grade. Remember that soil in the hole will settle after planting. So if you plant 4-6 inches above grade, in the end the settling will produce an at-grade planting. FORCE roots into the new native soil. Remove soil from the pot or ball to expose at least the outer roots so they will be engulfed by the ugly clay. Ammending the soil is OK up to one fourth added material. You probably won't actually see or feel a difference compared to unammended soil. That's good. Do not dig a hole deeper than the depth of the soil in the pot/ball and burlap ball.

DO NOT make clean abrupt sides to your hole. Roots have great difficulty crossing strongly defined soil interfaces. Soil interfaces can be good soil/bad soil, ammended soil/unammended soil, heavy soil/light soil, small particle soil/large particle soil, clay/gravel, whatever native soil/pot soil, loose soil/unloosened soil(even when it is the same soil!).

So the sides and bottom of the hole are going to be roughed up. When the hole is refilled, go around the sides of the hole with a digging fork. Facing the center, put the fork in the undug soil, 6 inches down, and gently pry the dirt toward the center of the hole, maybe about an inch. What you are doing is give that last gradient of transition of looser soil to the compacted hard soil surrounding the hole.

Do not give a little water everyday, rather water heavily once a week, or water heavily but only when actually needed.

Thanks for the advice! You've given us hope for creating a beautiful backyard. Leftwood, we will try the planting suggestions. And thanks, Helen, for the link to the U of M Extension Service. I am not feeling as gloom and doom about our backyard now.