What I know of a natural mosquito repellent is the neem tree, a small wood with slender stem and lots of green leaves. It is a decorative plant from India. A newspaper columnist for the agriculture section had written that mosquitoes are turned off by the neem tree so it is a natural mosquito repellent. A plant vendor had said that the citronella grass he is selling (planted in a plastic pot) is a better mosquito repellent. However, you have to cut the blades and compress it to let the scent of citronella come out which scares mosquitoes.