Lemon grass has long been used in natural insect repellents which contain citronella oil. Native to Asia, the grass can grow up to six feet tall and is quite an attractive ornamental grass. To help deter mosquitoes with its strong fragrance, plant lemon grass along walkways and in locations close to seating areas. Also, consider the image above. Plant citronella grass in large planters which can be moved around, function as a privacy screen and smells wonderful.