A harmful insect infestation, a problem that can easily snowball out of control, can dishearten a gardener. Fortunately, many plant species can ward off pests, in addition to producing beautiful flowers that compliment an established garden.
Flowering perennials native to Northeastern Europe and Asia, mums (chrysanthemums) produce fluffy, brightly colored flowers, many of which look similar to dahlia blooms. Besides being valued for their blossoms, mums are cultivated for their roots, which secret a substance that kills soil nematodes. Hardy mums can be grown in different types of soils, as long as they're well drained. Mums will generally survive with little attention in full sun locations in the garden. They are somewhat frost hardy.
Gardeners cultivate many of the 39 species of lavender (Lavandula) in warm climates. Most lavender plants produce small blooms in shades of purple, although some have white, blue or slightly gray flowers. Lavender has a strong aroma that's attractive to humans but unattractive to common garden pests such as rabbits and deer. Common lavender (Lavandula angustifolia), also called English lavender, is a top seller that thrives in full sun and well-drained soils. Take dried lavender in the house to ward off clothing moths.
Marigolds (Tagates erecta) require little maintenance. Gardeners cherish them for their blooms, which range in color from pale yellow to deep orange, and their ability to ward off pests. Marigolds possess a musky odor that makes them unappealing to many insects. Native to Mexico, marigolds love full sunlight. These colorful annuals require little tending as long as they are placed in a sunny location with moist, well drained soil.