Lemongrass is a frost-tender clumping perennial grass that is used as a lemony flavoring in Thai, Vietnamese, Laotian and Cambodian cooking, and is widely cultivated in Southeast Asia for that purpose. It is also an outstanding ornamental grass that lends great beauty to garden areas, regardless of whether it is used culinarily. Leaves emit a lemony fragrance when bruised. Extracted plant oils have been used for many years in herbal medicines and perfumes. Zone 9-11.