Sorry spoiler: Jacaranda may look like a nitrogen fixer, but it’s not. Nevertheless it is one of my all time favourite ornamental flowering trees.
The jacaranda mimosifolia is an evergreen, lush tree, that cascades purple flowers in spring and grows one of the hardest and most beautifuly shaped seed pods I know. It seems to be grown easily from seeds.
Here are the flowers and a seed pod from the year before. Image curtesy: Tatters