To grow cherry trees here in Kansas I planted them on terraces several feet high. We have similar clay / loam soil. Some root stocks are more tolerant of water than others so the type of trees you grow will be crucial.

This post was edited by ClarkinKS on Wed, Sep 24, 14 at 8:27

There is no precise equation I can offer, but a fully dwarf apple tree doesn't need a whole lot of well drained soil to function well. You could even take a 25 gallon pot, cut out the bottom, mix it with half sand and half your existing soil and sink it a third of the way into the soil and it would probably work. Just check it and make sure it drains well enough before putting in the trees.

If you want something fancier you can use stones or landscape blocks that are designed for the purpose and create about 5 or six foot diameter raised beds for each tree about 12" above the soil line. If you use about a third yard of sand and equal amount of compost for each tree, creating a gradually lighter soil (more and more sand) as you go up, you can even plant semi-dwarf trees. I've done that successfully with blue clay almost pure enough to make pots.

If you go for semi-dwarf, I recommend 111 rootstock because it functions well in wet soil. Most pear rootstocks are better than apples in heavy soils. Off the top of my head I can't tell you which dwarfing apple root is best but a quick search will reveal the answer.

Here is additional information on rootstocks
http://www.extension.org/pages/60228/effect-of-water-on-apple-trees:-not-enough-or-too-much#.VCN4BOktDmI

http://www.gardening.cornell.edu/factsheets/ecogardening/appleroot.html

This is one place to order rootstock and you can graft the rootstock later with the variety of apple you want

Here is a link that might be useful: rootstock

A lot of people think if stone or wood to make a border for a raised bed. Personally I prefer to mound the soil up to accomplish the same end. Think mounded rows in commercial orchards. I don't like to give a place for snails and slugs to hide during the day.

After installing trees and shrubs for my whole career I had a rule of thumb for amount I found worked for me and I could easily tell my employees.

UCDavis recommended that you NOT enrich the soil with compost when you planted. This tended to hold more water and caused more problems. If you mulch correctly you give your plants more water by keeping the sun from evaporating water during the day. 3" is great.

1 gal pot=1"-2"
5 gal pot=2"-3"
15 gal pot= 3"-5"
B&B or big box= 1/4 the amount of the root ball

Thank you guys I was being to feel like it would be hopeless.. I like the idea of mounded rows. Grafting is way beond me, but will look into trees grafted on to 111 root stock already.

how wide should mounded rows be? are there more worries about cold weather root damage in mounded rows?

The only problem with mounds, and I use them much more than some kind of walling method, is they tend to settle a great deal, so you need to make them about 18" high and at least 6' diameter for each free standing, say ultimately 12-14' high and wide tree (both can be adjusted up or down a couple feet). I keep the mounds from eroding by mulching with wood chips, which means you have to control voles even more carefully.

I don't know why someone would suggest that compost makes things wetter, that is recipe type gardening advice based on fear of a particular kind of compost, I think. Some composts repel water, some can be soppy but most composts help make clay drain better because it fits between the fine particles of clay and holds them apart, creating drainage.

Forest compost, especially the kind that forms under oak trees and white pines in the woods actually resists ever being soppy. If any of that happens to be handy you can gather it up and use it.

I deal with all these issues on a constant basis because I install orchards for people as a major part of my business. Drainage is often an issue so a high percentage of orchards I install are on mounds.

The commercial growers often use berms which has the advantage of maybe not needing to be as high, but I prefer individual mounds in home and estate settings..

Thank you for your help

You can make a raised bed/mound as high as you want. The tree's presence should help rehabilitate that underlying clay over its lifetime---though 90% of the roots will be in the first 3 feet of depth/70% the first foot.

As was said choose an appropriate rootstock for the area and one tolerant of wet feet, clay soil, poor drainage.

Here is a link that might be useful: plant a tree Raised bed