Has anyone ever tried these? Our backyard is a bit swampy and I read that the plants can deter mosquitoes.
It isn't hardy except in tropical areas if I remember correctly. I grew it one year in a pot on my back patio. I didn't end up using it in cooking, and didn't see any noticeable reduction in mosquitoes, so when it didn't survive the winter indoors, I didn't replace it the next year. I also grow lemon geraniums, and they don't make an appreciable difference in the mosquitoes, either, but they have a nicer scent and they do fine inside over the winter.
The one thing I have found that does make a difference in the mosquito population is putting mosquito dunks in the wet areas near my house. They contain a bacteria that infects only the mosquito larva so that they don't mature into adults. My ideal way to deal with bugs . . . non-toxic, narrowly targetted, and easy.