Common Name: smooth phlox
Type: Herbaceous perennial
Family: Polemoniaceae
Zone: 4 to 8
Height: 1.00 to 1.50 feet
Spread: 1.00 to 1.50 feet
Bloom Time: June to October
Bloom Description: Purplish-pink
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Naturalize
Flower: Showy, Fragrant, Good Cut
Attracts: Hummingbirds, Butterflies
Tolerate: Deer, Clay Soil
Culture
Easily grown in moderately fertile, medium moisture, well-drained soil in full sun to light shade. Prefers moist, organically rich soils in full sun. Plants are intolerant of drought and need to be watered in dry spells. Tolerates more soil moisture than most other species of phlox. Also tolerates hot and humid summer weather. Remove faded flower panicles to prolong bloom period. If not deadheaded, plants will self-seed in optimum growing conditions. Can slowly spread over time by both slender rhizomes and self-seeding to form large colonies.
Noteworthy Characteristics
Phlox glaberrima, commonly called smooth phlox, is native from Virginia to Wisconsin south to Florida and Texas. It typically occurs in moist meadows, low woods and along riverbanks. It is an upright, clump-forming, rhizomatous perennial which typically grows 1-3’ tall. Sweetly-aromatic, tubular, 5-lobed, rose to reddish purple flowers (to 1” across) with long corolla tubes are densely arranged in large, pyramidal, terminal clusters (panicles to 12” long) atop stiff, upright stems that seldom need staking. This is one of the few tall phloxes to bloom in spring (late April to May in St. Louis). Very thin, opposite, finely-toothed, lance-shaped, dark green leaves (to 4” long). As the common name suggests, this plant is essentially hairless.
Var. triflora is native to Southeast United States east of the Mississippi River but not including Mississippi. It differs from the species by its earlier bloom time and persistent overwintering basal foliage. Some botanists advocate it be elevated to its own species.
The genus name is derived from the Greek word phlox meaning flame in reference to the intense flower colors of some varieties.
Specific epithet means completely glabrous (without hairs).
'Forever Pink' was bred in 2007 by James R. Ault and Catherine S. Thomas of Chicagoland Grows, Inc.®,a nonprofit corporation of the Chicago Botanic Garden, The Morton Arboretum, and the Ornamental Growers Association of Northern Illinois in Glencoe, Illinois. Their goal was to breed interspecific Phlox hybrids that are well adapted to the climate and soils of the upper Midwest. 'Forever Pink` was derived from a cross made between an unnamed plant of Phlox glaberrima ssp. triflora as the seed parent and Phlox `Bill Baker` as the pollen parent. It forms a dense, uniform clump with upright stems with yellowish-green foliage and basal foliage that remains evergreen during most winters. It has sterile, one-inch-wide, purplish-pink flowers that have a peak bloom in early summer and will have a lesser repeat bloom through October, especially if the spent flowers are removed. Plants should be sheared to the basal foliage in late autumn or early spring. They grow 1 to 1 1/2 ft. tall and wide. United States Plant Patent PP#24,918 awarded September 23, 2014.
Problems
Although many species of phlox are susceptible to powdery mildew and root rot, this species of phlox is noted for having excellent resistance to both problems. It grows quite well in the St. Louis climate and is relatively maintenance free. Watch for spider mites, particularly in hot, dry conditions.
This cultivar is reputed to be completely powder mildew resistant.
Uses
Smooth phlox is an excellent spring-blooming phlox for the perennial border, cottage garden, wildflower meadow or native plant garden.