Tips dying back on crape myrtle

[luvinthemountains]

This crape myrtle stump in pot grew vigorously in the spring, but has now stalled and the growing tips on some branches are dying. Some leaves appear to be chewed on. Can anyone guess what is doing this? I have inspected the stems and undersides of leaves - no sign of bugs. This is sitting in my vegetable garden, on the ground.

 

[NOZZLE HEAD]

Has this progressed since the original post?

 

[luvinthemountains]

No, actually there was a second flush of growth that did not exhibit the same thing. It was, however, a different color than the first flush. Almost yellow. Maybe I can grab a photo in the morning.

 

[leatherback]

When I see this I am always first thinking .. roots.
I do not know the species so cannot be certain. But what are they growing in?