(Cymbopogon citratus) An easily grown perennial herb, essential to Thai and Southeast Asian cuisine and folk medicine. It is used to add lemon flavor to herbal teas or chopped finely in sauces and deserts. It will grow to 2-3' tall and spreads by numerous shoots sprouting from the base of the clump. It loves heat and summer sun and can tolerate drought but can be killed by freezing temperatures. Since it does well in a pot, Northerners can grow it outside spring through fall and just cut the top growth back and bring the pot in for the winter. USDA Zones 10-11.