Lemon grass is grown as both an ornamental grass in the garden and as a culinary herb. The tall, fountainlike sprays of lemon grass are attractive in both the herb garden and in ornamental flower beds. Lemon grass is a tender perennial, so it is grown as an annual in areas with freezing temperatures in winter. You can also grow it successfully in pots outdoors, then bring the lemon grass inside during the winter months. It is used in Thai and other Asian dishes for its mild, lemony flavor. Harvesting and preparing the lemon grass before using it in a recipe ensures it offers maximum flavor.
Harvest lemon grass when the stalks are 12 inches thick throughout the summer or harvest the entire plant in fall before the first frost. Cut off the stalks at the base of the plant with a sharp knife. If harvesting just a few stalks, cut off stalks from the outside of the plant and leave the interior stalks in place to continue growing.
Peel off the outer leaf or leaves from the stalk, as these are tough and fibrous. Chop off the bottom root section and the upper green portion with a sharp knife, leaving behind just the white lower section of the lemongrass.
Crush the remaining white stalk by grinding it in a mortar and pestle. Alternately, grate it with a fine grater to extract the lemon grass pulp. Add it to the dish you are cooking as directed in the recipe.
Place the entire stalk in water if the recipe calls for sliced lemon grass. Boil for 10 minutes, then remove and drain. Slice the now-tender lemon grass and add to the recipe.