Tall Flatsedge

Tall flatsedge is a tufted, rhizomatous sedge with solid triangular stems, narrow basal leaves and rounded heads of golden-brown spikelets. It grows in damp-to-wet places and flowers in summer, with stems commonly about 16–24 inches tall and occasional stems approaching 36 inches ([Burke Herbarium](https://burkeherbarium.org/imagecollection/taxon.php?Taxon=Cyperus+eragrostis); [USDA NRCS](https://plants.usda.gov/DocumentLibrary/plantguide/pdf/cs_cyer.pdf)). ## Landscape Use Use it along a pond edge, in a bog garden or in another wet planting where its upright sedge texture fits a naturalistic design. The USDA guide records this species in shallow water and moist ground; the Burke Herbarium lists damp-to-wet shores and ditches. Its clump can spread outward, so give it a defined edge or use a contained wet planter instead of placing it where it could overrun neighboring plants. ## Growing Conditions Keep the root zone consistently moist. Tall flatsedge suits sites that stay damp between waterings and can grow in shallow water; the USDA guide also notes it in irrigated gardens. Its golden-brown flower heads add summer texture above the leaves, then develop seed that can disperse beyond the original clump. ## Maintenance Check the planting edge through the growing season and remove unwanted seedlings or rhizome fragments while they are easy to reach. The USDA guide cautions that Cyperus can establish readily and may outcompete other plants; it advises against introducing it into native plant communities. Confirm local guidance before planting, and use containment where spread would be difficult to manage.