Catnip, also called catmint, is a member of the mint family that is known to repel mosquitoes. A study headed by researchers from Iowa State University found that nepetalactone, an essential oil found in catnip, was 10 times more effective than DEET, a compound found in commercial insect repellents.
Lemon balm, basil and peppermint are other members of the mint family known to repel mosquitoes. Other garden plants reputed to repel mosquitoes include marigolds, lavender, citronella grass, rosemary, calendula, garlic, cloves, eucalyptus and tea tree. Wild plants with a similar reputation include cedar, sagebrush, wild bergamot, wormwood, mugwort, snowbrush, sweetfern and nodding onion.