Get a long thin rod and poke around and see if it's what you think it is.
Is it possible that the root ball is compacted and nowhere for roots to grow like a pot plant that never gets potted up? Or perhaps the roots are in a tight ball and become water repellent (hydrophobic)
Add a little wetting agent, see if there's improvement.
The leaves dont look like they're dry/crisp though, no dogs doing there thing on it is there?
You haven't fertilized or maybe something washed down there?