Five of the most effective mosquito repelling plants

1. Citronella is a common natural ingredient in mosquito repellents. The aroma is a strong smell that masks other attractants to mosquitoes. It is used in 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 in climate zones where frost does not occur. Citronella plants are considered low maintenance.They do best in full sun and well-drained locations. When purchasing citronella, look for the true varieties, Cybopogon nardus or Citronella winterianus.

2. Horsemint (or Bee balm) is an adaptable perennial plant that gives off a strong incense-like odor that confuses mosquitoes by masking the smell of its usual hosts.
Horsemint 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. It is often found in coastal and beach areas.  Horsemint leaves can be dried and used to make herbal tea. Its flowers will also attract bees and butterflies to your garden.

3. Marigolds are hardy annual plants with a distinctive smell that mosquitoes find particularly offensive. Marigolds contain Pyrethrum, a compound used in many insect repellents. Marigolds prefer full sunlight and reasonably fertile soil.  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. Besides repelling mosquitoes, marigolds repel insects that prey on tomato plants, so you may want to plant a few marigolds in your tomato bed for added protection.

4. 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 that 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.

5. Catnip is a natural mosquito repellent. 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, Nepeta cateria, is very easy to grow. Some people apply crushed catnip leaves or catnip oil for more robust protection. 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.
Many commercial insect repellents contain from 5% to 25% DEET. There are concerns about the potential toxic effects of DEET, especially when used by children. Children who absorb high amounts of DEET through insect repellents have developed seizures, slurred speech, hypotension and bradycardia.