The best flowering vines to cover or adorn a pergola are those that climb, produce showy flowers and survive in the growing conditions of your region. When these vines are perennial species, they become low maintenance landscaping plants that deliver colorful, attractive flowers every year. In some cases, a flowering vine for your pergola is not winter hardy, but you can still find ways to grow it on the structure every year.
A form of wisteria with the scientific name of Wisteria macrostachya is a particularly effective species for pergolas, according to the Missouri Botanical Garden. The cultivar known as Blue Moon has a wide growing range in North America, able to grow from U.S. Department of Agriculture plant hardiness zones 3 through 9. Blue Moon becomes quite heavy, but a pergola will support its weight. Growing to 25 feet, Blue Moon turns out blue flowers in drooping clusters as long as 12 inches in June. Subsequent blooming occurs during the summer. After the flowers pass, seedpods similar to 5-inch long beans develop in their place, staying on into winter.
Solve the problem of what to do with an ornamental yam vine (Dioscorea discolor) in places where it is not winter hardy by removing the tubers it develops from before the first frost. Take the tubers out after the initial fall frost and keep them in a cool spot before planting them next to your pergola the following spring. This vine is evergreen and winter hardy in USDA zones 9 through 11, producing variegated, heart-shaped foliage. The leaves are a mix of green, white, silver, purple and red. The white flowers bloom in clusters and they are aromatic. This native of Ecuador grows to lengths of 12 feet in a single growing season, easily climbing up a pergola.
Butterflies and hummingbirds show up regularly to attend to the flowers of the red passion flower (Passiflora coccinea), a flowering vine native to the tropics. Red passion flower is suitable to grow on a pergola in USDA zones 10 through 12, where it matures to between 10 and 12 feet. This vine produces the most flowers when in full sun, a consideration when deciding where on your pergola to grow it. Red passion flower blooms from July into September, then gives the added benefit of yielding an edible fruit as long as 3 inches.
Trim back any new and unwanted growth on the silver lace vine (Fallopia baldschuanica, since this native of China is somewhat invasive when it gets the chance to expand. Growing to between 15 and 25 feet in length and able to survive from USDA zones 4 through 7, this is one of the best flowering vines due to how long it blooms. The white flowers emerge in July and continue to bloom until the first frost. Able to grow in an array of soils, the silver lace vine grows in sun or partial shade, with some tolerance for drought.
Missouri Botanical Garden: http://www.mobot.org/gardeninghelp/plantfinder/plant.asp?code=C753
Missouri Botanical Garden: http://www.mobot.org/gardeninghelp/plantfinder/plant.asp?code=A506
