Lemon verbena is native to South America, specifically Argentina and Chile, and was imported to Europe during colonial times. Lemon balm is native to Europe, where it has been used for centuries as a flavoring, an herbal remedy, and even in bee-keeping to attract honey bees and encourage them to stay in a hive.
Lemon verbena sports tiny white flowers in clusters that invite pollination from butterflies. The leaves are bright green and spear-shaped. Lemon balm looks more like its mint cousins, with fat, serrated leaves. Its small white blooms grow in circles around the stem, inviting bees to pollinate. It is so attractive to bees, in fact, that it is commonly referred to as Melissa, the Greek word for bee.
Lemon verbena is planted in butterfly gardens to attract the brightly-colored garden visitors, while lemon balm is planted near fruit and berry plants that require bee pollination to draw bees into the garden. Lemon verbena is used more often for fragrance, though it may be used for flavoring, while lemon balm is used often for flavoring or herbal remedies and only sometimes for fragrance.
Lemon balm is hardy from U.S. Department of Agriculture zones 5 to 9, and is grown commercially through much of Europe and North America. Lemon verbena is more heat-loving, and is hardy from zones 8 to 10. It is grown commonly in the southern areas of the United States, through Mexico and South America. It can be grown in greenhouses in colder climates.