Nothing is more irritating to me than seeing plants labeled with misleading or outright false information. In the case of plants labeled as ‘mosquito repellents’ (ex. citronella, lemongrass, rosemary, mints, catmint, and lemon balm) these are sadly, inflated claims. While essential oils of these plants can be made into homemade repellent sprays, having a little geranium sitting on your picnic table will be far from helpful in keeping those little buggers away.
Just to clarify, a 2018 scientific study at Michigan State University did show that some of the aforementioned plants will repel mosquitos. However, the insects will still buzz right up to the plant and even land occasionally on them, just not as much as on other plants. With that being said, mosquitoes are attracted to the CO2 we exhale. So simply walking by your mosquito repellent plant will be enough to catch their attention and draw them to you nonetheless. Also keep in mind that all plants in the mint family tend to be very invasive, and have the uncanny ability to escape their pots or flower beds and spread to undesirable areas like lawns and the middle of shrubs.
Instead of wasting your money on planting mosquito repellent wishes, try instead to attract the things that eat mosquitoes! Dragonflies for instance, can eat up to 15 percent of their body weight in mosquitoes and gnats. That’s hundreds of mosquitoes consumed by a single dragonfly every day! Plant flowers that will attract dragonflies: white yarrow, black-eyed Susan, and meadow sage, just to name a few.
If you wish to provide the perfect home for dragonflies, consider putting in a small pond with at least two feet of depth to keep the water cool. Stagnant water is a perfect breeding ground for mosquitoes, so keep water moving with a small pond pump. Even a whiskey barrel made into a pond is a great start. (Please rethink this idea if you have toddlers though!) Fill your pond with waterlilies, reeds, and other water or bog plants which provide cover for dragonfly eggs and nymphs. You can purchase a mosquito ‘disk’ that floats in the water for any mosquitos that may be using any part of the pond to breed. The disk contains bacteria that only affect the mosquitoes, not dragonflies.
Bats love a good meal of mosquitoes too. Brown bats can eat nearly 1000 mosquitoes in a single hour! Here in Washington, we have more than 15 different species of bats. There are many tutorials online on how to build and place a bat house, and it’s nice to know that with all their acrobatic flying at night, they will be clearing out all the mosquitoes in your yard!