A: The citrosa is actually a scented geranium. Many plant oils are somewhat repellent to insects – lemon balm actually contains more citronellal oil than the citrosa does. If you rub the plant leaves on your skin, insects will be kept away for a short time. One experimenter estimated plant oils to be 40 – 60 percent as effective as DEET, the active ingredient in Deep Woods Off. If you depend on the plant to keep mosquitoes away from your patio, the results may be much less than you desire. The citrosa is grown as an annual in Atlanta. It may be perennial in places where frost is rare.