Aha, from Wiki:
http://en.wikipedia.org/wiki/B...
Classification
The genus Buddleja is now included in the figwort family, Scrophulariaceae;[5] it had earlier been classified in either the Loganiaceae or in a family of its own, the Buddlejaceae
So I too vote for Buddleja with the alternative spelling of buddleia as the 'also sold as' that zuzu suggested.
