Many of our gardens start to wane at this time of year, with the flowering plants beginning to flop and looking sad. English gardens tend to be at their best in early summer, with the fresh flush of growth, full of lupins, delphiniums, peonies and roses. By the end of summer, the garden can look lacklustre and there’s an urge to cut everything down to the ground, leaving it bare and featureless till spring. But it doesn’t have to be that way.