About 3-4 years ago, I planted a tree-form Ninebark 'Diablo'.
Love it in this spot.... it replaced a damaged peashrub.
Anywho, over the course of that time, the tree/shrub has sunk about 3-4" below the surrounding soil level and has gone crooked. The original container was about 18" across and it's basically that 18" width that has sunk.
I know I should not put soil on top of the root ball. My instinct is to try and uproot the tree and put about 4-5 inches of compacted soil into the bottom of that hole.
What would y'all recommend?