Rumors and misinformation abound regarding plants that will repel mosquitoes in home landscapes. Common plants purported to repel mosquitoes include catnip,peppermint, rosemary, marigolds, Eucalyptus and Artemisia species, to name a few. None of them will repel mosquitoes by merely growing in a landscape. The volatile oils purported to have repellent properties are released when plants are crushed or burned. No data exists to support their effectiveness as repellents.
A type of scented geranium (Pelargonium citrosum “Van Leenii”) is marketed exclusively for the purpose of repelling mosquitoes – the “Mosquito Plant”. Studies out of the University of Guelph have found no repellent properties. While it does give off a lemon scent when leaves are crushed, it does not contain the essential oil Citronella (commonly found in mosquito repellant sprays, lotions and candles) known to repel mosquitoes.
The best control is still to minimize any standing water in the area and use an effective mosquito repellant that contains DEET. Chemical or biological controlmethods(mosquito dunks, bricks, or sprays) will kill larval and/or adult mosquito populations in small areas such as a backyard. For moreinformation visit, http://extension.colostate.edu/topic-areas/insects/west-nile-virus-and-mosquito-management-frequently-asked-questions/ or http://extension.colostate.edu/mosquito-management/