Tibouchina sp., Lasiandra or Princess Flower

March is the month when the rich glowing purple flowers of Tibouchinas can be seen at their best in gardens up and down the east coast. They are normally associated with the New South Wales town of Alstonville where there is a festival in March to celebrate this beauty from Brazil. Some species of Tibouchina can grow to be tree size up to 10 metres but most are well rounded shrubs to about 3 metres with soft velvety green leaves with the odd leaf turning scarlet during cold weather. It only tolerates light frost and prefers a rich soil with adequate water . Older shrubs can become a bit sparse with die-back occurring on some branches but it otherwise tough.White and pink flowering cultivars are also available but it is the iridescent and gaudy purple flowering form which is the real winner.
Tibouchina can be grown under trees for more frost protection without any reduction in flower quantity.

Tibouchina showing purple and white flowering forms

2017 update: I don't have plants of it available for sale