Just when we are ready to hit the backyard deck or patio and enjoy some time outdoors, insect pests, especially mosquitoes, seem to have the same idea. If you are looking for a way to make these intruders buzz off without having to resort to harmful chemicals, you don’t have to look any further than your local garden center or nursery.
There are actually a number of plants that are naturally repellant to insects such as mosquitoes (also known as the state bird of Mississippi). When you are planning your summer plantings, why not include some varieties that look great, are easy to grow and will help to keep pests from spoiling your outdoor activities.
Ageratum emits a smell which mosquitoes find particularly offensive. Ageratum secretes coumarin, which is widely used in commercial mosquito repellents.
Ageratum is a low-lying annual ornamental plant, which reaches heights of 8 – 18”, and is easily recognized by its blue flowers, although there are varieties with pink, white and violet blooms. This plant will thrive in full or partial sun and does not require rich soil. It is often displayed in rock gardens where low-lying plants are favored.
Although the leaves of ageratum can be crushed to increase the emitted odor, it is not advisable to rub the crushed leaves directly on the skin.
Bee balm is an adaptable perennial plant, which repels mosquitoes much the same as citronella, a better-known natural repellant. It gives off a strong incense-like odor, which confuses mosquitoes by masking the smell of its usual hosts.
Bee balm is a fast growing, shade-tolerant and drought-resistant plant which reaches a height and width of 2 – 3 feet. It does well in dry, sandy soil and can tolerate salty conditions, which is why it is often found in coastal and beach areas.
Mature bee balm plants can be propagated in spring and fall by dividing into small sections and transplanting into permanent locations. It can also be planted in pots for moving indoors in cold weather.
Bee balm leaves can be dried and used to make herbal tea. Its flowers will also attract bees and butterflies to your garden.
Marigolds, commonly grown as ornamental border plants, are hardy annual plants, which have a distinctive smell mosquitoes find particularly offensive. Marigolds contain Pyrethrum, a compound used in many insect repellents.
Marigolds prefer full sunlight and reasonably fertile soil. Although marigolds can be planted from seed, starter plants are inexpensive and readily available at most garden centers. Although an annual, a marigold plant will often reseed itself in favorable conditions, or their seeds can be collected for future germination. Established plants will need to be thinned, and flowers should be dead-headed to promote additional blooms.
Potted marigolds can be positioned near entrances to your home and any common mosquito entry points, such as open windows. The smell may deter mosquitoes from going past this barrier. While marigolds can be used as border plants around the patio, we do not advise putting marigolds on the patio table since the bright blooms may attract wasps.
Besides repelling mosquitoes, marigolds repel insects, which prey on tomato plants, so you may want to plant a few marigolds in your tomato bed for added protection.
Catnip also is a natural mosquito repellent. In August 2010, entomologists at Iowa State University reported to the American Chemical Society that catnip is ten times more effective than DEET, the chemical found in most commercial insect repellents.
Catnip is very easy to grow. This perennial herb is related to mint, and grows readily both as a weed and a commercially cultivated plant in most areas of the US.
While catnip will repel mosquitoes in close proximity to the plant, some people apply crushed catnip leaves or catnip oil for more robust protection. Bear in mind, however, that cats will respond to you similarly as they would respond to the plant itself. Cat owners may want to choose an alternative plant for repelling mosquitoes.
Citronella is the most common natural ingredient used in mosquito repellents. The distinctive citronella aroma masks other attractants to mosquitoes, making it harder for them to find you. Although citronella is used in many forms, such as scented candles, and torches, the living plant is more effective because it has a stronger smell.
Citronella is a perennial ‘clumping’ grass, which grows to a height of 5 – 6 feet. It can be grown directly in the ground. If grown in the garden or near the patio, it should be planted in the ‘background,’ behind small decorative flowers and shrubs.
Gardening centers usually sell citronella as small plants in pots, ready to transplant to a larger pot or into raised garden beds on the ground. Once established, new plants can be propagated in early spring by splitting large clumps into smaller sections and replanting the new ‘starts’ in pots or other areas of the garden. Citronella plants are considered low maintenance, like most grasses, and they do best in full sun and well-drained locations.
Other herbs, such as mint, garlic, chives, lemongrass and rosemary also are great for warding off mosquitoes and ants. Not only can you dine outdoors in peace but your barbeque fare of grilled chicken, roasted potatoes and salads get an extra flavor punch from all of these fabulous herbs you can add to them.