Smooth Phlox is a clump-forming perennial native to Southeastern and Central US. In North Carolina, it can be found mainly in the Piedmont and mountains but also in a few coastal areas on stream and river banks, open bottomland forests, swamps, marshes, sedge meadows, and tallgrass prairies. Smooth Phlox prefers fertile, moist, well-drained soils in full sun to light shade and will need irrigation during dry spells. Rhizomes also help form colonies. The showy rose to purplish blooms appear in spring on tall panicles and attract pollinators. The deep green, narrow foliage is also attractive. Deadheading will help prolong blooming; it will otherwise self-seed. It can be used in borders, along ponds or streams as it is tolerant of soil moisture, in naturalized areas, or in native wildflower gardens. It has excellent resistance to powdery mildew and root rot. Insects, Diseases, and Other Plant Problems: Watch for spider mites, phlox bugs and stem nematodes. Diseases include powdery mildew, leaf spot and root or crown rot. More information on Phlox .
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; High Organic Matter; Loam (Silt); Sand
Soil pH
Acid (<6.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist | Occasionally Wet
Available space
12 inches-3 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 2 ft. 0 in. - 4 ft. 0 in. | Width: 2 ft. 0 in. - 2 ft. 6 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Clumping; Erect; Spreading
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Opposite
Leaf shape
Lanceolate; Linear
Leaf margin
Denticulate; Entire
Leaf feel
Glossy
Leaf value
Good Cut; Showy
Leaf size
3-6 inches long, < 1 inch wide
Hairs present
No
Leaf detail
Leaves are deep green, thick, glossy, with bluntly pointed tips, rounded at the base, and with a prominent central vein. They are very thin, hairless, and arranged in 10-20 opposite pairs along the stems. Lower leaves are either sessile or clasp the stem, while upper leaves are sessile.
Flower color
Pink; Purple/Lavender; Red/Burgundy; White
Flower value
Fragrant; Showy
Flower form
Panicle
Flower shape
Dome; Tubular
Flower size
< 1 inch
Flower detail
Individual flowers are up to 1 inch across with 5 flat, rounded petals. The lower part of the corolla is fused into a narrow tube. Stamens are visible at the opening to the corolla tube. Blooming occurs for 6-8 weeks from late spring into summer.
Bloom time
Spring; Summer
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Narrow seed capsules contain many small seeds and display from June to July.
Wildlife & Ecology
Native status
Native
Origin
Central and Southeastern U.S.
Distribution
AL , AR , FL , GA , IL , IN , KY , LA , MD , MO , MS , NC , OH , OK , SC , TN , VA , WI , WV
Wildlife value
Smooth phlox attracts butterflies including Monarchs, Swallowtails, and Sulfurs as well as the caterpillars of the Spotted Straw and Olive Arches moths. Syrphid flies may feed on the pollen. Hummingbirds may also drink the nectar. The leaves and stems are attractive to rabbits and groundhogs, and less frequently by deer.
Attracts
Butterflies; Hummingbirds; Moths; Pollinators; Small Mammals