Tree identification: empress tree

Self-tutoring about trees one notices: the tutor mentions the empress tree.

There are a few trees around town that someone told me are empress trees. They have purple flowers that appear in clusters; when in bloom, they’re spectacular. The ones I’ve noticed have already flowered this year. I believe one such tree can be found along Dogwood.

I’ve only noticed three empress trees around town, but I guess in some places they are viewed with caution because they can spread quickly.

Source:

milnergardens.viu.ca

southernliving.com