Lemongrass, also known as lemon grass and citronella grass, is a perennial grass that grows in tropical climates. The stalks grow in clusters, similar to spider plants, and can reach anywhere between six to ten feet in height. A stalk of lemongrass consists of a pink base, a few tough green husks, and a white core, which is what is used in cooking.
To use fresh lemongrass in your cooking, always cut off the lower bulb and remove tough outer leaves. The main stalk (the yellow section) is what is used in Thai cooking.
Lemongrass is also thought to have numerous health benefits, especially when used in combination with other Thai spices such as garlic, fresh chilies, and coriander.