Crape myrtle are deciduous trees which means they drop their leaves in the fall and go dormant until the spring. Pruning right before dormancy is bad. Pruning during dormancy is the preferred time. We have a bougainvillea , about 5 years old, outside our patio. I do not fertilize or water, but it grows like a weed.
Bougainvillea can be frustrating.
They often flower erratically and then overgrow an area with their aggressive, thorny stems. Some of the confusion and disagreement on cultural requirements is also caused by the differences in the bougainvillea species that are available on the market. Some species of bougainvillea tend to be more constant in their flowering while other species tend to flower better after dry periods. New cultivars are being developed each year and there is work on some thornless cultivars too. Unfortunately, most nurseries do not provide you with the name of the bougainvillea species or cultivar.