We live in Arvada, Colorado and have a 5 year old Hackberry about 20 feet tall. This year it started falling over and the leaves are slightly blotchy and droopy. I ignored the droopy leaves because I know bugs get on the leaves and I have to spray it twice a summer to kill them and get the leaves to bounce back. We staked the tree and packed soil and mulch around the trunk over a month ago, but I can still push on the trunk and move it. The leaves at the very top also seemed to be turning yellow and falling off before any other trees on the block (around the end of August). After reading some other questions with Hackberries though, I'm wondering if the new flowers and dirt we put around the tree this year is too deep and it is either smothering the root or its not getting enough water because of the flowers.
Jefferson County Colorado trees and shrubs
If you can push on the trunk and move it, then there is probably something wrong with the roots. It sounds to me like the tree may not have ever established itself. One way this could have happened is if the tree was planted too deeply. Look at the trunk where it goes into the soil. If it looks like a telephone pole, then the tree is planted too deep. It could be that the tree leaves were drooping the last couple summers because the roots have not established well enough to absorb enough water to help it through the hot dry weather we had in June and in August. Last year was very hot and dry, even more so than this year.
If hackberry trees are planted too deeply, they can also develop encircling roots which could result in the symptoms you describe.
There isn't anything you can do if the tree was planted too deep.
Yes, the new soil you put around the tree is a problem as is the mulch and soil you packed around the trunk. I suggest removing it as soon as you can.
The early yellowing and defoliating is a typical symptom of tree stress. I suspect that poor root establishment and/or girdling root is the cause. There is no cure for this problem.