The very short leaf stalks could point to Quercus robur also. It won't be long before these plants start producing more characteristic leaves and you will be able to tell for sure. Another problem with piggy backing on an existing thread is the party that started the thread may get sent an e mail notification every time somebody posts a comment to the thread.

Not enough to go on - esp. the pieces that have been dead for some time

Specifically that looks just like a Tonto Crape Myrtle,...just planted one in my front yard 6 mos ago and have been getting WOW's since the red blooms came out. It could also be a Pink Velour Crape Myrtle also, as both have the red blooms, only the Tonto will grow a few feet taller. I also have a Muskogee Crape Myrtle in the prime front lawn spot, that guy will top out around 15 - 16 Ft. Now have a total of 5 CR's,...easy maintenance,..minimal watering & fertilizing,..just what I was looking for as I get older ! LOL

Thanks y’all! Interesting that it’s likely a New Zealand lemonade...do you happen to know about how long to takes the lemons to ripen? We’ve have them for about 6 months and they are still green. @Dave thanks! I googled more images and it does appear to be leaf miner. We will probably try some neem oil and hopefully the leaves come back strong next year.