These plants that deter biting insects in your yard are generally easy to grow, hardy and also have culinary and medicinal uses. The essential oils in the stems and leaves of the plants repel insects and are more effective if they're crushed and rubbed on the skin, according to Donald Lewis at Iowa State University. The leaves or flowers can also be crushed and steeped in alcohol to make a natural insect repellent.
Pennyroyal has a distinct minty aroma. The plant repels fleas, mosquitoes and flies. It should be grown in sandy soil with good drainage and needs partial to full sun. Plants should be set 1 to 2 feet apart and watered regularly. Some varieties, like American pennyroyal are drought resistant and a good choice for xeriscaping. Others prefer an almost boggy soil. Ask at your garden store for the variety that best suits your needs. The essential oil in pennyroyal can be toxic to humans and animals.
It takes up to 3 years for lavender to reach full size. The fragrant plant repels fleas, mosquitoes and moths and should be planted in areas with good drainage. Set plants 2 to 3 feet apart and keep them watered until they're established. Once mature, lavender is drought resistant and is a good choice for flowering hedges. The plant does not need to be pruned. Harvest the blooms for use in sachets to repel moths indoors.
Rosemary repels many insects including non-biting bugs that attack your other plants. It's a hardy plant and can grow to a bushy 4 feet tall. Plant seedlings in full sun about 2 feet apart and water them regularly. Blooms are pink, blue or white depending on the variety. Birds and butterflies are attracted to rosemary. Harvest the small pine needle-like leaves for use in cooking.
Clumps of lemongrass, or citronella grass can grow to 6 feet in height. Citronella nardus has the most insect repellent qualities and is commonly used in candles to repel mosquitoes. Plants should be set about 3 feet apart in full sun or partial shade and watered regularly. The leaves can cause skin irritation so don't plant lemongrass along walkways or in play areas. The plant has a lemony aroma and is used in cooking.
Catnip repels mosquitoes and mice. It can be an intrusive plant. It self-seeds, so if you don't want your garden overrun, pinch off the blossoms as soon as they fade. Volunteer plants can be easily uprooted. Catnip can grow up to 4 feet tall and should be planted about 18 inches apart in full sun or partial shade. Water the plant regularly. If you have problems with cats in your garden, plant catnip away from the garden.