When planting Buddleja find a nice sunny spot and dig a hole twice the size of the pot the plant has been grown in. Once you have placed plant into the hole, fill with extra compost. This allows the roots to get into the ground better. Water well to establish, but bear in mind that Buddleja do not like ground that gets water logged in the winter. Pruning when the plant finishes flowering will ensure a tidy, impressive display.