A lot of people come here after googling "Princess Plant" because of this post about my then-new Tibouchina urvilleana.
Update: She continues to do well in the shady spot where I planted her. I know they like full sun, but I don't have a lot of full sun in my backyard. She has bigger leaves than most other princesses; I imagine that's an artifact of growing in a shady spot.
Except for removing some crossed branches, I've done little pruning, but pruning is definitely in her future--especially when the sun moves back across the sky next spring and she can expect several hours of full sun every morning. She will have an open, airy canopy, not the dense, shrubby habit of other princesses. She's there to arch over the pond and stream (still in progress).
I planted her in a sawed-off oak wine barrel I bought at a local nursery. I tipped a nursery worker $30 to saw out the bottom too, for better drainage and future root growth. The barrel also serves as a structural element holding up half of a terrace that's retained by a rock wall along the rest of its perimeter.
Knowing she'd be in shade, I was reluctant to put her in the native, poorly-draining California clay soil. Most people, I believe, put their princesses in native soil, but I wanted to be more careful about drainage since she's growing in the shade. According to the wiki, princess plants come from Latin and South America.
I haven't noticed many butterflies flocking to her, but late summer and fall may not be the time for butterflies in San Francisco--I don't know. The blossoms have been large and abundant, but short-lived--usually just 2-3 days. Generally, 10 blossoms are open at any time, and she's still pretty small--no more than 3-4 feet in any dimension.
More news later. With pictures. Here's one.