Lavender (Lavandula spp.) is an herbaceous perennial notable for its silvery foliage, its subtly attractive flowers and its distinctive aroma. The plant's strong scent comes from essential oils in its leaves and flowers, and on top of adding an attractive perfume to the garden, the aroma may also help to deter garden pests such as browsing deer and biting mosquitoes.
Most varieties of lavender are winter-hardy in U.S. Department of Agriculture plant hardiness zones 5 to 9. Spanish lavender (Lavandula stoechas), however, is hardy only in USDA zones 7 to 9.
Lavender Oil as a Repellent
A study published in 2006 in the Journal of Medical Entomology concluded that a solution containing essential oil derived from lavender was effective at repelling mosquitoes. The study found that a weak solution containing 1 percent lavender oil had only a weak repellent effect, but a solution of 30 percent lavender oil was 100 percent effective as a repellent.
Although the mechanism by which lavender and other essential oils repel insects is not yet entirely understood, some research suggests that the oils contain chemicals that interfere with the insects' nervous systems, and in high concentrations some oils are fatal to insects.
Using Lavender Oil
Some commercially available natural repellent products contain lavender oil, along with essential oils derived from other plants. If you'd prefer to make your own lavender-based repellent, you can do so using either lavender oil or the fresh leaves of a lavender plant.
To make your own mosquito repellent using lavender oil, dilute approximately 30 drops lavender oil with olive oil into and 8 ounce spray bottle and apply the solution directly to your skin. To be sure that the solution doesn't cause skin irritation or an allergic reaction, apply first to a small area of skin and watch for a reaction before applying it to large areas of your body. Do not apply to children under two.
To make a repellent with fresh leaves, make a lavender-oil infusion using alcohol as a medium. Crush fresh leaves with a mortar and pestle to begin releasing the plant's essential oils and then put the crushed leaves in an 8 ounce spray bottle filled with rubbing alcohol or vodka. Allow the solution to sit for at least 12 hours before spraying it on your skin and clothing.