4. Ageratum
Also known as Flossflowers, Ageratum emits a smell which mosquitos 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.