Some of the best plants for late-summer-to-early-fall color, such as chrysanthemums, asters, and 'Autumn Joy' sedum (shown), tend to flop over just when they're about to bloom. Mix's solution? Cut back the stems by a third when the plants are about half their expected height. "They bloom later," Mix says. "But they stay lower to the ground, so they don't splay as much." Similarly, she selectively cuts back several lavender plants in each cluster when they're 1 to 2 inches tall. "Doing this can move back their bloom time by two to four weeks for a second wave of color."