Thin out bushy perennials
SOME clump-forming perennials, such as sedums, can produce so many shoots that when flowers develop, the outer shoots are forced to the ground and the rest flop down on elongated stems. You can prevent this from happening, by thinning out some of the young shoots to give the rest more space. Snap them out or cut them off at the base with secateurs. Take off up to half the shoots, evenly throughout the clump. The result will be stout upright flowering stems.