I also have a 4 year old peach tree, that just didn't come back this year.  It's just dead.  In other years it would produce an abundance of fruit.  

Hello,

I am sorry to hear that your fruit trees are dying.

There could be a couple of different issues going on.

One- the planting depth may have been too deep- here is information on proper tree planting: https://cmg.extension.colostate.edu/Gardennotes/633.pdf

Two - it wasn't clear to me from your question whether you watered over the winter.  Newly planted trees especially need watering every month or so in the winter.

Three- were the trees a hardy variety for Colorado? We had a severe cold snap in February, and any trees that were marginal may not have survived. Young trees are also more susceptible to cold snaps. You can help them by mulching around the roots (but don't pile it near the tree).  

The suckers you see are probably from the root stock, and not the tree you planted. Suckers will never grow to be a structurally sound tree.

Another possibility - was any herbicide sprayed anywhere near the trees?  Possibly a weed and feed in the lawn?

Finally, one more possibility.  If you have clay soil, you may have been watering the trees too much.  Waterlogged soil can weaken the roots and reduce oxygen.  Only water when the soil is dry to a depth of 2 inches, and then water deeply.

Hello,

I don't think the sewer line is the issue, unless there is a leak.

I think I can see that one tree was a Bing Cherry - sweet cherries don't tend to do that well in Colorado. Pie cherries such as Montmorency are more reliable.  I don't know about the other trees, because I can't see them, but there may a hardiness issue.  Not many peach trees are hardy enough to do well here, and we did have a very deep freeze in February that did get to almost 17 below zero - so any marginally hardy tree may have died.

I do think the trees also may be planted too deep, and that in combination with perhaps overwatering a clay soil could be weakening the roots, which would decrease hardiness.

Okay...I'll search out the Montmorency trees you spoke of, and not plant them to deep.  

Can I use clay buster to mike in with the clay based soil I have now in  my yard?

You could try clay buster, but proper planting depth and proper watering will go much further to correct the problem.