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// SPECIES PROFILE · GRASS · FULL-SUN · MESIC · NATIVE · POLLINATOR

Yellow-fruited Sedge

Carex annectens

Yellow-fruited Sedge is a medium-sized, clump-forming sedge of wet prairies, moist meadows, and seasonally flooded lowlands in eastern North America. Its common name comes from the distinctive yellowish-green to golden-brown color of its maturing perigynia (the flask-like structures enclosing the seeds), which gives the flowering culms a warm, honey-toned appearance in late spring and early summer. The foliage is a dense cluster of bright green, narrow leaves that forms a tidy, fountain-shaped clump. In NE Oklahoma, Yellow-fruited Sedge is a workhorse plant for rain gardens, bioswales, wet prairie restorations, and the vegetated edges of detention basins, where its fibrous root system stabilizes soil and its dense foliage filters runoff.

// QUICK FACTS
Family
Cyperaceae (sedge family)
Life cycle
Perennial; densely clump-forming (cespitose)
Native range
Eastern and central US — ME to FL, west to ND, NE, KS, OK, and TX; Ontario
USDA hardiness
Zones 4–8 (Tulsa = 7a/7b)
Mature size
1–3 ft tall; 1–2 ft spread per clump
Bloom
May – July; flowering culms rise above the leaves
Flower/Fruit
Yellowish-green to golden-brown perigynia in dense, erect spikes; wind-pollinated
Sun
Full sun to part shade
Soil
Moist to wet; tolerates clay and seasonal flooding; pH 5.0–7.5
Water
Medium to wet; requires consistent moisture
Wildlife
Seeds eaten by waterfowl and songbirds · cover for amphibians · larval host for skippers and moths · soil stabilization
Yellow-fruited Sedge (Carex annectens) with yellowish-green seed heads and fine green foliage
Carex annectens — the dense clump of fine green foliage and the yellowish fruiting culms that give the species its name. Photo: Rooted Revival.

Identification

[ field key — yellow perigynia · dense clumps · wet habitat · narrow leaves ]

Habit & Foliage

A densely cespitose (clump-forming) perennial sedge without creeping rhizomes, forming tight, rounded clumps of foliage. Leaves are basal and alternately arranged along the culm, narrow (2–5 mm wide), bright green, with a prominent midrib and slightly rough margins. The foliage is semi-evergreen in mild winters, often persisting with a yellowish cast. The leaf sheaths are tight and often tinged with reddish-brown at the base.

Flowering & Fruit

Flowering culms rise 1–3 ft, slightly above the leaves, in May–July. The inflorescence is a compact to slightly elongated cluster of 4–10 spikes, each ovoid to cylindrical and densely packed with perigynia. The perigynia are the key identifying feature: yellowish-green when immature, ripening to a warm golden-brown or honey-brown at maturity, giving the fruiting culms their characteristic warm color. Each perigynium is flattened, ovate, 2–4 mm long, with a short, two-toothed beak. The species name "annectens" means "connecting" or "linking," referring to its intermediate position between related Carex species.

Habitat & Range in NE Oklahoma

Carex annectens is native across the eastern and central US, from Maine to Florida and west to the Great Plains. It is a species of wet to mesic prairies, sedge meadows, floodplain openings, wet ditches, pond margins, and seasonally flooded depressions. In NE Oklahoma, it is common in wet prairie remnants, the moist margins of farm ponds and detention basins, and along drainage ditches and swales in both rural and suburban settings. It tolerates the seasonal fluctuation between saturated spring soils and drier summer conditions that is typical of the tallgrass prairie landscape.

Yellow-fruited Sedge is a facultative wetland plant (FACW) in the National Wetland Plant List and is a reliable indicator of moist-to-wet soil conditions. In the Tulsa region, it is one of the most common sedges in disturbed wetland sites and is often found in the vegetated basins of constructed stormwater management features, where it volunteers readily from seed.

Ecology & Wildlife Value

[ waterfowl seed · skipper host · amphibian cover · soil stabilization ]

Wildlife Food

The seeds are consumed by dabbling ducks, rails, sparrows, and other wetland and prairie birds. The dense clumps provide cover for frogs, toads, and small wetland invertebrates. Like most Carex species, the foliage is a larval host for various skipper butterflies and moths, including several satyrs and wood nymphs.

Soil Stabilization & Filtration

The dense, fibrous root mass is excellent for stabilizing wet soils, filtering sediment from runoff, and taking up excess nutrients. Yellow-fruited Sedge is a useful component of the vegetated shelf or basin of a rain garden, where its clumping habit allows water to flow between plants while its roots bind soil particles.

Horticulture & Care

Yellow-fruited Sedge is a tough, adaptable, easy-to-grow sedge for moist to wet, full-sun to part-shade locations. It is ideal for rain gardens, bioswales, pond margins, wet meadow plantings, and drainage swales. Plant container-grown starts or plugs in spring or fall, spacing 12–18 in apart. It will not spread aggressively (unlike rhizomatous sedges) but stays in tidy, expanding clumps that can be divided every 3–4 years. Once established, it requires no supplemental water except during extreme drought and no fertilizer. Cut back dead foliage in late winter before new growth emerges.

Sources & Further Reading

Hero photo: Rooted Revival.