Lemon balm is a herb which when taken as a tea calms the nerves. It acts as mild sedative and helps in getting sound sleep. Lemon Balm essential oil help is used in aroma therapy.
I find it easy to grow and it has a strong lemony flavor.
Lemon Balm
Cheers 
I am really sorry but I think above shown plant is not a lemon balm. it is only simple mint plant.
Ok Ajay I respect your observation. The packet of seeds with which I grew them had lemon balm printed on it.