Answer: Tibouchina, your princess flower, prefers slightly acidic, well-draining soil and full sunshine. The brilliant royal purple flowers should appear intermittently from late spring into winter. You can help encourage blossoming by pinching out the growing tips so the plant develops new flowering wood. It's safe to fertilize in early spring and again in mid-summer to promote growth and bloom. Use a 5-10-10 fertilize and apply according to the rates listed on the label. If your soil is alkaline (which I suspect, given your gardening zone), use a fertilizer that's acidified (made for acid-loving plants). Be sure to water your plant regularly during the growing season to keep it healthy and vigorously growing.
Without knowing what your other plant is, I can't really recommend you pull off the spent flowers, nor can I predict whether it will bloom more than just during the spring season. Based upon the time of bloom, you might have wisteria (clusters of flowers that hang downward like grape clusters), or you could have clematis (6-petaled, star-shaped flowers). In either case, they bloom only in the spring and it isn't necessary to remove the spent flowers. Hope this information helps!
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