This is Verbena bonariensis, also known as Purpletop Vervain, Brazilian Verbena, clustertop vervain, Argentinian vervain , tall verbena, pretty verbena, South American vervain, and Upright Verbena. This versatile flower has many uses. It works well as a dried flower or a cut flower. It is also a great plant to have if you want to attract birds, bees, and butterflies into your garden. These plants need to be grown in the full sun where they can get at least 6 hours of direct sunlight per day. They can get about 4 feet tall full grown and they stay in bloom from the middle of the Summer until the middle of the Fall. Tall Verbena is a nectar plant for the American Lady, Cabbage White, Great Spangled Fritillary, Painted Lady, Pearl Crescent, Pipevine Swallowtail, Zebra Longwing, Zebra Swallowtail, Silvery Checkerspot, Fiery Skipper, and Great Southern White butterflies. Verbena bonariensis is also a larval host plant for the Common Buckeye butterfly. The hummingbirds love this plant too. USDA Hardiness Zones 7 to 10