I have a self set Buddleia in a pot and although it looks healthy the leaves are yellowinf is there anything I can do ?

perhaps try feeding it. you don't say how big the pot is. They are hungry feeders when given the opportunity.

You'll get the best of the flowers if you feed it too. Just a sprinkle of growmore will do. Prune off all the flower stems quite severely after they've died back too. It'll grow more bushy next year & be less likely to blow over in Winter

Thankyou