There is a white form also (but I don't grow that). My purple one sometimes sets seeds. It also benefits from a very hard prune every two years and sends up fresh and vigorous canes. Yes Bananafan I dare say we have a lot of unique native plants down here, but I am always interested and awed by the variety of the plants of nth america esp the wildflowers. I very much admire the resilience of keen gardeners there who go thru a winter I can only imagine, here in sub-tropical queensland, which is about as balmy as Floriday, I suppose. Anything you ever fancy in the line of seeds that I can help out with, just mention, I can only try. EXCEPT bananas :-(

Hypoestes aristata? Here is a link that might be useful:

There are other types of tibouchina that I don't think are quite as demanding, perhaps? At least mine wasn't, until I killed it by moving it in hot weather. Here's a photo of the one I had, peeking out from behind my rudbeckia triloba, though I don't know which one it is. It was really pretty. Bloomed well for me in a large container for a long time before going into the ground. Then it bloomed well there, until the fatal shovel came along! I don't suppose anyone can tell which one it was from this poor photo? Marcia

Perhaps hoary vervain, Verbena stricta. Look that one up and see if it matches.