This.
I don't have an HOA, thank goodness, but we had to cut the heart/top out of the tree in front of my house as it was dead from neglect. The previous owners of this house were a special kind of stupid about lawn care, house maintenance, and house upgrades.
That same year I bought some fertilizer that is targeted at the type of tree from these folks, and then watered the crap out of it. By watered the crap out of it, I mean I turned the hose on low, and let it deep soak for 2-3 hours every couple/3 days.
It has now filled in the top and center of the tree, and it looks good.