Answer: As you have discovered, Tibouchina urvilleana (Princess Plant) produces blooms on new shoots. To keep it blooming all season long you'll want to prune it back to encourage the development of new stems. You don't have to shear it back like a hedge, but you should shorten individual stems begining in spring and continuing all summer to encourage a dense growing plant with lots of new stems developing throughout the plant. This will give you lots of blooms all over the plant.
Best wishes with your Princess plant!
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