It is important to know that it is the compounds found in these plants that repel the mosquitoes. Just placing these plants around your area without also protecting yourself is often not very effective for each individual. By crushing, drying or infusing with oil it can be applied to your skin and clothes. It's as simple as grabbing a handful of plant material and rubbing it on your skin and clothes when you go outside. Planting mosquito repellant plants will also benefit your pets. Microfilariae are parasites that give your pet heart worms and are transmitted by the mosquito. Having these plants in your yard will help in reducing their exposure.
With the threat of the West Nile virus, the need for insect repellent when venturing outdoors is essential and necessary. Many of your commerical products contain 5% to 25% DEET. Not sure what DEET is? Take this link: National Pesticide Information Center. The potential toxic effects of this chemical has always been a real concern for me. Especially when being used on children.
Mosquito Repellent Plants
Citronella Grass - Cymbopogon nardus
Citronella grass is the most commonly used ingredient in natural insect repellants. Very similar to lemon grass (Cymbopogon citratus) but with a much stronger and different smell. To tell the difference between the two, just look at the stems. Citronella grass has red stems, lemon grass stems are green. Citronella is a perennial ‘clumping’ grass which grows 5' - 6' tall. It can be grown directly in the ground where frost does not occur, otherwise, use as an annual.
Horsemint - Monarda citriodora
Native to the U. S. Plains, this drought tolerant plant grows up to 3' tall with lavender/pink colored flowers from May through July and possibly into September/October if watered. Although it's an annual, it can reseed for the following year with the added bonus of being a great butterfly, hummingbird and bee attractor. Read "The Importance of Bees" to learn more about the problems we are having with our worlds pollinators.
Catnip - Nepta cataria
A beautiful and easy to grow perennial with light purple flowers that bloom summer through the fall. Research has shown that it is more effective than DEET. Take this link to read more about it. Catnip Repels Mosquitoes More Effectively Than DEET
Marigolds - Tagetes spp.
An annual bedding plant, marigolds repel more than just mosquitoes. Marigolds have such a strong scent that mammals, insects and well as some people don't like them. I've always planted marigolds in with my vegetable garden to keep away pests.
Eucalyptus - Eucalyptus spp.
Eucalyptus oil has long been used as an insect repellant as well as other uses. Caution must be used though. When used externally eucalyptus is non-toxic, but taken internally eucalyptus is toxic. Maureen McCracken is a master gardener in Mecklenburg County, NC.
and has written a short description of the benefits of eucalytus and is very informative. Medicinal Herbs: Eucalyptus
Rosemary - Rosemarinus officinalis
Rosemary is not just used for cooking. The strong scent rosemary gives off makes an excellent mosquito repellent. "How to Use Rosemary Oil as an Insect Repellant" gives you a recipe for making your own. Rosemary is drought tolerant and loves the heat. Good drainage is a must. Many cultivars are available from ground covers to upright