Phlox, a hardy herb with clusters of small, brightly colored flowers. It is related to the gilia. Phlox is an erect or trailing plant with pairs of narrow or lance-shaped leaves. The flower consists of five flat, petal-like lobes arising from a short tube. In most species the flower has an eye-like center marking. Most of the 50 species are native to North America.
Phlox is a favorite garden flower. It is used in borders and rock plantings, and thrives in full sunlight. The many domesticated varieties are descended from a few wild species. Annual phlox, native to Texas, is an erect plant about 18 inches (45 cm) tall, with dense clusters of 1-inch (2.5-cm) flowers that may be almost any color except yellow. The similar perennial, or garden, phlox, native to the southeastern United States, grows about four feet (120 cm) tall.
Other cultivated phloxes include the moss pink, or ground pink (not a true pink), and wild sweet William (not related to the sweet William of the pink family). Both of these phloxes also grow wild in the eastern United States. Moss pink, an evergreen with tiny, needle-like leaves and pink or magenta flowers, forms a matted ground cover. Wild sweet William is an erect plant with a purple-spotted stem and loose clusters of purplish-pink blossoms.
Annual phlox is Phlox drummondi; perennial, P. paniculata; moss pink, P. subulata; wild sweet William, P. maculata or P. divaricata. All are of the phlox family, Polemoniaceae.