I advise you to do nothing except water it deeply every fourth day. It will look like it is dying for about 2 to 3 weeks, but crepe myrtles are very hardy and it will bounce back once it gets accustomed to its new location.
Once it is established, cut back on the watering to once a week. Crepes can go for for long periods of time without water, once their root system takes hold.
Next spring, you should prune its limbs back about halfway down each limb. This will allow it to bloom again in summer.
If you cut it back deep, it will take longer for the tree to reach a good height. But once you are satisfied with how tall the myrtle is, then you can prune it back to just above bottom of the limbs near the stalk. When its new branches shoot out , it will be loaded with blooms.
Once it is established, cut back on the watering to once a week. Crepes can go for for long periods of time without water, once their root system takes hold.
Next spring, you should prune its limbs back about halfway down each limb. This will allow it to bloom again in summer.
If you cut it back deep, it will take longer for the tree to reach a good height. But once you are satisfied with how tall the myrtle is, then you can prune it back to just above bottom of the limbs near the stalk. When its new branches shoot out , it will be loaded with blooms.