Ditto what Mr. Mass said, it needs more water.
*We are remedying that as we speak (watering the whole area for an extended amount of time).
I would move the flowers to another location, they are competing with the tree for moisture and if it scarce they will win.
*I have thought about that, too. Hopefully, the new watering style will help and we are SUPPOSED TO get rain for five days next week. Everyone keep your fingers crossed!
I would suggest moving the limestone slabs? from around the tree and create a mulch ring. Mulch will help maintain some moisture and still allow air to get to tree roots. Slabs will compact soil and cause other problems.
*When we planted the tree, we dug into a shallow hole in the yard and placed the tree in it. Then, we placed a large box around the hole and filled to the top of the root ball with dirt. Really, that box (not slabs) is just some landscape timbers and is barely sitting on the grass. All of our other trees have mulch around them-- I'm not sure why my husband didn't do that with this tree. No mulch, I think. I'll make that suggestion, though. Thank you for all of the good ideas!