This month’s featured native: Slough sedge (Carex obnupta)
Perhaps you’ve heard some variant of this botanical rhyme: “Sedges have edges, rushes are round, and grasses have knees that bend to the ground.” This month’s native, with its sharply triangular flower stalk and prominently v-notched leaves, is a shining example of the first part. A perennial graminoid growing from tough, spreading rhizomes, slough sedge is a workhorse species for wet areas. As the only native evergreen sedge species in our area, it is relatively easy to identify at this time of year. The central culm is surrounded by 2-5 leaves, reaching anywhere from 30-150 cm (1-5 ft) in height; leaves are all on the lower quarter of the stem, and arch gracefully outward. The male flowers are in 1-3 tall, terminal spikes, while female flowers appear in (2-4) dangling clusters, somewhat reminiscent of catkins; these may be anything from 1.5-5 cm (5/8″ – 2″) long. Both are purple-brown in color; male flowers have yellow pollen at peak bloom, and females may have white, sticky “webbing” protruding at that time. The seeds are lens-shaped achenes, smooth, brown, and quite small at roughly 2 mm (<0.1 in).
While the seeds allow slough sedge to reproduce at a distance (traveling by water or animal), much of the plant’s reproduction is done through rhizomatous spread, which it does quite eagerly. The tough, fibrous roots and long rhizomes allow the plant to provide excellent erosion control on streambanks and shorelines (slough sedge will tolerate brackish water); wet meadows and (unsurprisingly) sloughs are also common habitats for this species.
In addition to shoring up near-water areas, slough sedge improves water quality by taking up nutrients; it is very commonly used in rain gardens and bioswales. Slough sedge also provides important food and habitat for a wide variety of birds and mammals, and has been in use as weaving material for basketry and other applications for millennia.
