Don't think its anything in the Solanaceae family or Buddleia, flowers make
me think of a very small Datura/Brugmansia but I don't think there is one,
and it should not be hardy, though that depends where you are.
When does it flower? and any chance of a closer shot of the flowers.
Finally if it sets seed, what sort of seed pod, and any chance of a few?

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk