Q.crape myrtle leaves dry out
The leaves on my 1 year old crape myrtle started to dry out, starting from the top of branches. Tree is potted, was on the deck and was watered occasionally. Tried fungicide and didn’t see difference.
Die back that starts at the top could be a sign that your crepe myrtle sustained some kind of cold injury. I know that Florida did have some cold spells this year. But, let's confirm that. I recommend that you conduct a scratch test on your crepe myrtle. Scratch the outer bark of a major trunk near the top with a fingernail or a knife. If you don't see a green layer underneath then your tree is dead from at least the scratch up. Keep scratching lower and lower until you see green.
Another possibility is that you are under-watering your crepe myrtle. You mentioned watering it "occasionally". If the soil feels dry to the touch, I would definitely water it. Young crepe myrtle trees in particular have more water requirements than their mature counterparts, which are usually drought-resistant.
For more information on crepe myrtle trees, please visit the following link:
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/tips-to-grow-crepe-myrtles-in-containers.htm
https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/crepe-myrtle-care.htm
