Most people who live in this area of Indiana have to contend with clay soil in their landscape. Almost anyone who is landscaping in areas around new construction will have this problem as a lot of topsoil is removed with construction. Adding compost, good topsoil and peat over time will help to improve your soil and make growing landscape plants easier.
The ability of the soil to both retain and drain moisture helps your plants thrive through periods of drought and constant irrigation. Plant roots are able to reach and use nutrients from the soil and water easier when they are not packed in hard clay. Plants can establish a root system that allows them to anchor themselves so that they will avoid loosening and falling during storms.
There are a couple of important things to remember when planting and landscaping in clay soil:
Don't ever dig a hole to plant and remove the soil that was there; replacing it with a "better" soil. The clay around the hole will become a "bowl" for water and can easily drown the plant. Instead, use the soil that you've removed from the hole and add some better topsoil, compost or peat to the loosened clay. Mix well and refill the hole around the plant roots.
Never try to improve your clay soil with sand. The clay can become more like concrete with that addition.
We found a couple of good resources that help you to decide how best to improve your soil. A very detailed article from Fine Gardening Magazine helps you to determine if you have clay and what to do about it. Another from Organic Gardening explains how to raise your bed with organic matter to improve your soil conditions, and a brief article from Proven Winners explains the benefits and fixes for clay.