Phlox glaberrima aka Smooth Phlox

Phlox glaberrima is a perennial known as smooth phlox. It belongs to the Polemoniaceae family. Its native range covers central and eastern parts of the United States. It grows from Virginia and Wisconsin south to Florida and Texas. Wild plants grow in damp meadows, marshes, and low woods. They also grow beside streams and rivers. The species name refers to its lack of hairs.

Plants form upright clumps and spread through slender rhizomes. Sources give heights of 1–3 feet [0.30–0.91 metres] and 2–4 feet [0.61–1.22 metres]. Garden plants can therefore reach 4 feet [1.22 metres]. Clumps span about 2–2.5 feet [0.61–0.76 metres]. The firm stems seldom need support. Dark green leaves grow in opposite pairs along them. Each leaf is narrow, lance-shaped, hairless, and often glossy. Fine teeth line the leaf edges. Lower leaves may clasp the stem, while upper leaves lack stalks.

Fragrant flowers crowd into panicles at the stem tips. Their colours range from pink to reddish purple, with some white. Each flower has a narrow tube and five rounded lobes. Flowers reach about 0.08 feet [0.025 metres] across. Missouri records place bloom in April and May. North Carolina reports six to eight weeks from late spring into summer. Removing spent flower clusters can extend the bloom period. Narrow capsules hold many small seeds in June and July. Plants can seed themselves when conditions suit them.

Smooth phlox grows best in fertile soil with good drainage. It prefers moist soil rich in organic matter. Full sun suits it best, though it accepts light shade. It grows in clay, loam, or sand, with acid to neutral soil. It tolerates brief wet spells, summer heat, and humid air. Drought does not suit it, so dry spells call for watering. Most sources list USDA zones 3–8; Chicago also lists zone 2. Gardeners can raise plants from seed or divide established clumps.

Use it in borders, cottage gardens, and native flower meadows. It also suits pond edges and stream banks. The flowers provide material for cutting and draw butterflies and hummingbirds. Syrphid flies may feed on pollen, while moth caterpillars use the plant. Rabbits and groundhogs browse its leaves and stems. Deer browse it less often. Sources report strong resistance to powdery mildew and root rot. These diseases can still occur, along with leaf spot and crown rot. Watch for spider mites, phlox bugs, and stem nematodes. The supplied sources do not establish human edibility or toxicity.