The phlox plant genus contains numerous species of perennial and annual plants. Named for the Greek word meaning “flame,” phlox flowers add vibrant colors to gardens and landscapes. Gardeners should select phlox according to intended use, bloom time, flower color and appropriate hardiness zone. Various types of phlox do well in the United States.
The sand phlox (Phlox bifida) variety naturally occurs in the central regions of the United States and does well in United States Department of Agriculture (USDA) Hardiness Zones 4 to 8. This mat-forming perennial reaches between 3 and 6 inches high and spreads out 6 to 12 inches. Sand phlox prefers well-drained soils in fully sunny locations and can tolerate drought conditions. The sand phlox features green leaves and light blue flowers that appear in May. Gardeners often plant sand phlox in rock gardens, wildflower gardens, borders and cottage gardens.
Wild Sweet William
Wild sweet William (Phlox divaricata), also called woodland phlox, performs well in USDA Zones 3 to 8. This perennial naturally occurs in woods and fields across central United States. This mat-forming phlox variety reaches up to 12 inches in both height and spread. Flower clusters appear in April and May, featuring petals in pink, purple or blue shades. This phlox likes moist, rich soils in partly to fully shady sites. Wild Sweet William sometimes suffers from powdery mildew disease. Spider mites often feed on the foliage in hot, arid climates. This phlox variety works well in rock gardens, naturalized areas, wildflower gardens and borders.
Smooth phlox (Phlox glaberrima) tolerates higher moisture levels than other types of phlox. Indigenous to the southeastern U.S., this clump-forming plant reaches 4 feet in height and 30 inches in width. Smooth phlox blooms in April and May, featuring aromatic flower clusters of white, pink, red or purple blossoms. This perennial needs semi-shady to fully sunny locations. Gardeners often plant smooth phlox in borders, woodland gardens and wildflower meadows.
The creeping phlox (Phlox stolonifera) grows along stream banks in the southeastern U.S. This phlox variety does well in USDA zones 5 to 9, and prefers organic, acidic soils with constant moisture. Creeping phlox plants range from 6 to 12 inches in height and 9 to 18 inches in width. Fragrant purple flower clusters bloom from July through September. Creeping phlox works well as ground covers in shade gardens, woodland gardens and native plant gardens.
The moss phlox (Phlox subulata), sometimes called the moss pink, is native to central and eastern U.S. and performs well in USDA Zones 3 to 9. This mat-forming variety reaches up to 6 inches in height and spreads out about 2 feet. Fragrant flower clusters bloom from March through May, featuring pink, red or purple blossoms. The moss phlox prefers moist, humus-rich soils that recieves full sun. Foliar nematodes occasionally occur during extended periods of wet weather. This sun-loving plant works well as a groundcover, edging or a foundation plant.