Our garden is currently hidden under several inches of snow but the Tibouchina urvilleana plants in our small conservatory, which would be more at home in tropical Brazil than in freezing north-east England, are in full flower. Each bloom only lasts for a couple of days but they are produced in a long succession through the darkest months of winter. These plants have very unusual flowers, with two types of stamens. The lower, claw-shaped ones are the genuine article, producing pollen that is squeezed out of a pore in their tip when they are pushed downwards, but the upper ones with pale tips are sterile 'food' stamens that attract bees. They use the pollen- bearing stamens as a landing pad and unwittingly transport the pollen.
Tibouchina urvilleana grows into a greenhouse shrub but old, woody plants soon become shapeless and their brittle stems easily snap. I've found that the best way to grow them is to take semi-ripe cuttings in summer, when they root very easily, producing compact plants with plenty of 3 inch diameter flowers from November onwards.