Rhynchospora colorata aka Starrush Whitetop

Rhynchospora colorata is a grass-like perennial in the sedge family. Its common names include star sedge and whitetop sedge. Its native range runs from the southeastern United States into northern South America. It also occurs in Mexico, Central America, and parts of the West Indies. Wild plants grow on sandy coastal plains and in marsh edges. They also grow in wet hollows, roadside ditches, and coastal dunes.

Plants reach 1–2 feet (0.30–0.61 metres) tall. Mature clumps spread 2–3 feet (0.61–0.91 metres) wide. Slender rhizomes spread slowly beneath the soil and form dense clumps. The upright growth gives the plant a grass-like outline. NC State describes its foliage as evergreen. The narrow leaves reach 0.33–1 foot (0.10–0.30 metres) long. They are simple, hairless, and arranged alternately. The stems have no scent.

Small, cream-white spikelets form round heads at the stalk tips. Flower stalks reach about 1.25 feet (0.38 metres) tall. Each head has a ring of four to seven leaf-like bracts. These white and green bracts give the display its star-like shape. They can make the heads look like small daisies. Missouri Botanical Garden lists bloom from May through August. NC State extends the season into September. Fruit appears from June through October. Bees and butterflies visit the flowers. The plant also draws songbirds and small mammals.

Grow star sedge in full sun or part shade. Keep the soil moist to wet throughout the growing season. It accepts sand, loam, and clay, including sites with poor drainage. It tends to favor alkaline soil. Plants can grow partly submerged in shallow water. They also cope with brief flooding by brackish water. Salt in coastal air is tolerated, but direct salt spray is not. Missouri Botanical Garden lists hardiness in USDA zones 7–10.

Use this sedge beside ponds or in bog gardens. It also suits the damp parts of rain gardens. Within its native range, it can spread along streams and wetlands. Its pale flower display adds contrast to its narrow leaves. Divide clumps when they outgrow their space. Seed offers another way to raise new plants. Cut back old growth in winter to clear space for spring shoots. Care needs are low where moisture stays steady. Missouri Botanical Garden reports no major pest or disease concerns.