BrooklynStart said:Dewberry, I also have an area of heavy clay. My areas of clay are due to builders most likely storeing supplies/heavy equipment. For my clay, I can dig down about 3 feet, often more, to improve drainage. During winter rains, without improvement, I can could dig down and puddles will form--STILL FIGHTING ONE ARE THAT I WISH TO PLANT A JAPANESE MAPLE, AREA POOLS IN WINTER.
In my clay area, I have rototilled 2inches (+/-) cow manure to the clay area. In the area I wish to plant the maple, I removed dug holes with a post hole digger and replaced the soil with both organic matter and soil from a different area, and still have puddles during winter rains. Our summers normally require irrigation of lawns and flower beds. During winter rains, puddles do form, and some plants grow (hydrangeas, Korean spice viburnums, lupine, Dutch Iris, plus many others--as long as they are not deer food).
Hopefully, your area of clay is due to the builder and not natural. Without regard to cause, the only method I know about for one to improve clay soils is add organic material ( do not add sand, I am told it can create a concrete type soil).
MINOR EDITINGS WERE MADE TO MY ORIGINAL REPLY AFTER NOTHING THAT THIS POST WAS ALSO MADE ON THE "ASK A QUESTION" FORUM, AND REPLIED TO BY RpR. I agree with RpR's post.