If the annuals have stopped flowering during the summer, they can usually be induced to bloom again either by severely cutting the plants back or by applying fertilizer. 1 Grown for its colorful foliage. 2 Can be dried for winter arrangements. 3 Should be planted in the fall or late winter. The easiest way to protect against serious insect or disease problems is to closely observe the plants.
Early detection is important because it often is impossible to stop a severe problem.
Most insect problems on annuals are caused by aphids, spider mites, white flies or caterpillars. Aphids are small, soft-bodied insects usually found on the stems and the underside of foliage of plants. The most common aphid on annual flowers is light green in color with wings present only at certain times of the year on the adult insects. Aphids feed by sucking sap from the stems and leaves of infested plants and can cause heavy loss in certain situations. Aphids may be controlled by spraying with Malathion, Diazinon or other registered insecticides on a weekly basis until the population has been controlled.