If phlox is not presently a part of your garden, now may be a good time to look at garden catalogs and place your order for some of these highly adaptable plants. Most are herbaceous perennials that range in size from 3- to 4-inch groundcovers to tall 4- to 5-foot tall plants. All species bear clusters of five-petaled flowers with tubular bases. The species below offer myriad choices for gardens and country or city roadsides where they will bloom for many years.
Commonly called woodland phlox, wild sweet William, or wild blue phlox, this adaptable plant is hardy from Zones 3-9. A hardy native, this phlox is often found along streams and in open woods, but it is equally at home at the front of a flower border. It is evergreen in most of the South and spreads at a moderate rate by rhizomes. The species bears lavender flowers and has thin dark green leaves 1½ to 2 inches long. In spring delicate 1½-inch rosy-lavender to soft pink, five-petaled flowers are held on upright stems above the foliage. Woodland phlox can be grown in sun if moisture is sufficient but will go dormant during a drought.
In its native habitat, woodland phlox grows under deciduous trees where it receives sun during the winter and early spring and is shaded during the summer. Moist, humus-rich, well-drained soil is preferred. Propagation is by seeds, cuttings, or division of established clumps.
Some cultivars to look for include: ‘Clouds of Perfume' (ice-blue, faintly fragrant flowers), ‘Fuller's White' (fragrant, pure white flowers), ‘Dirigo Ice' (pale blue), ‘Laphammi' (lavender blue flowers), ‘Blue Moon' (deep violet blue), ‘Louisiana Purple' (deep purple flowers), ×‘Chattahoochee', a cross between woodland phlox and prairie phlox (lavender blue flowers with a maroon eye), and others.
Annual or Drummond phlox, hardy from zones 3-10, is native to Texas but has been planted widely throughout the country where it provides mile after mile of spring color in roadside plantings. The much branched, sticky-glandular plants grow 6 to 18 inches tall and produce clusters of flowers of various colors including white, red, peach, lavender, and bicolors. Growth is best in full sun. Plants are drought tolerant, but best growth occurs when planted in rich soil and watered regularly. Plants are usually started from seeds.
Cultivars include: ‘Fordhook Finest Mix' (a strain that includes white, lavender-blue, pink, buff-yellow, and bicolors), ‘Brilliant' (bright, dark-eyed rose-colored flowers), 'Chanal' (pink double that looks a little like a rose), as well as some dwarf strains of assorted colors that include ‘Globe', ‘Dwarf Beauty', 'Petticoat', ‘Twinkle', and 'Palona'.
Meadow or spotted phlox, as it is sometimes called, is hardy in Zones 3-8. Meadow phlox is an upright (to 3 feet tall), clump-forming, rhizomatous perennial that blooms in early summer with dark pink, fragrant blossoms. It is native to the Appalachian region and appreciates moist but well-drained, rich soil and full sun to partial shade.
Plants self seed and spread by rhizomes to form large colonies. Flowers are borne in large, cylindrical, terminal clusters up to 12 inches long at the tips of the stiff, upright, red-spotted stems. Thin, opposite, finely-toothed, lance-shaped, dark green leaves are up to 5 inches long.
Look for cultivars ‘Flower Power' (white speckled with light pink), ‘Natascha' (pink and white bicolor), ‘Rosalind' (dark pink), ‘Alpha' (medium pink), and ‘Miss Lingard' (white).
Garden or summer phlox, hardy from Zones 4-8 and native to the eastern half of the United States, is perhaps the showiest of all the phloxes. It appreciates rich, well-drained soil and full to partial sun. Growing up to 5 feet tall, it puts on a colorful show with its fragrant, dome-shaped flower clusters from mid to late summer.
Deadhead to prevent self-seeding since volunteers will revert to less attractive colors. Pinch in early spring to induce branching. Divide every few years and replant vigorous plants from the outer edges of the clump. Propagate by division or from cuttings. Choose mildew resistant cultivars, especially for the humid South.
Phlox paniculata cultivars include ‘David' (white), ‘Mt. Fuji' (white), ‘Prospero' (white with blush of pink), ‘Bright Eyes' (pink with crimson eye), ‘Delta Snow' (white with purple eye), ‘Eva Cullum' (pink with red eye), ‘Franz Schubert' (lilac pink), ‘Laura' (purple with white eye, ‘Nicky' (deep magenta), ‘Red Indian' (rosy pink), ‘Starfire' (brilliant scarlet), ‘Robert Poore' (iridescent purple), and others.
Creeping phlox (Zones 4-8) is a groundcover to 8 inches tall that spreads by runners and bears pink to purple blossoms in spring. Hairy rounded leaves stay attractive throughout the summer. Native to deciduous woods of the East, it likes moist, humus-rich soil and part shade. Some cultivars are ‘Bruce's White', ‘Pink Ridge', and ‘Sherwood Purple'.
Commonly called moss phlox or thrift, it is a soft, needlelike cushion of green most of the year, but for about four weeks in spring it is completely covered with small flowers in shades of white, lavender, pink, rose, or red. This prostrate, mat-forming, evergreen perennial grows 3 to 6 inches tall and spreads by stolons to cover an area 18 to 24 inches wide. It is native over much of the United States and is hardy in Zones 3-9.
Best performance is in full sun and relatively poor soil. Fertilize lightly in spring and water weekly during dry weather. Growth is best if divided every three or four years. Divide plants in fall or winter.
Popular cultivars include ‘Oakington Blue' (light blue), ‘Candy Stripe' (rose pink edged with white), ‘Coral Eye' (white with a coral eye), ‘Snowflake' (white), ‘Scarlet Flame' (scarlet), and ‘Maiden's Blush' (light pink). More information about moss phlox is available on Dave's Garden.
Species names of the Phlox genus are very descriptive.
"Paniculata" means "in panicles" and tells that the flowers of P. paniculata are borne in clusters called panicles.
"Subulata" means "awl-shaped", referring to the needle-like leaves of P. subulata that swell slightly at their base.
"Divaricata" means spreading or diverging and is a good name for P. divaricata because flowers spread out in a wide angle from the stem.
"Maculata" means spotted; Phlox maculata has purple-spotted stems.
P. drummondii was named after Thomas Drummond, a 19th century Scottish naturalist.
P. stolonifera spreads by stolons.