My chrysanthemums tend to be very tall and fall over when they bloom. Are you supposed to trim them back at some point so they maintain their compact shape and flower in the fall?
Many gardeners "pinch back" their garden mums to maintain a more compact form. This simply means to prune the plant lightly. Everywhere you make a cut, new growth will emerge, making the plant fuller. This procedure usually begins in spring when the plants are about 6 to 8 inches tall. Take a sharp pair of pruners and cut the entire plant back by about half. Repeat the process about 2 or 3 times over the course of the spring and into early summer. The rule of thumb is to make your last pinch by the 15th of July. Any later than this and you run the risk of delaying the plant’s bloom too long, and you may lose your blooms to frost. If time gets away from you and you don’t start pinching back your mums in the spring, don’t worry. Even if they have already started setting flower buds you can still cut them back as late as July and still have blooms in the early fall. Just prune them down to about 12 inches tall and give them a dose of all-purpose liquid fertilizer to stimulate growth. Mums are dependable, workhorse plants in the fall garden. Their ample blooms are perfect for adding bold splashes of color to containers and flower borders. By selecting early, mid and late flowering varieties you are guaranteed to have a continuous wave of color from September through November!