Slough Sedge (Obnupta)

The Slough Sedge (Obnupta) is generally described as a perennial graminoid. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The greatest bloom is usually observed in the mid spring, with fruit and seed production starting in the spring and continuing until summer. Leaves are not retained year to year. The Slough Sedge (Obnupta) has a moderate life span relative to most other plant species and a rapid growth rate. At maturity, the typical Slough Sedge (Obnupta) will reach up to 3 feet high, with a maximum height at 20 years of 0 inches.

The Slough Sedge (Obnupta) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by seed, sprigs. It has a slow ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -3°F. has low tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Ethnobotanic: The leaves of Carex obnupta, are used for both wrapping and twining in the grass baskets that are well known and widely marketed by Nitinaht and Nootka women even today (Turner et al. 1983). Grass baskets are created using three-cornered grass (Scirpus pungens) for the basket bottom and ribs, slough sedge for the wrapping, and the top rim is made of the inner bark of western red cedar (Thuja plicata). The baskets usually have tightly fitting, convex lids of the same weave, and usually both basket and lid have designs of whales, birds, canoes, or geometric patterns woven with dyed strands of twining materials.

The Nitinaht believed that picking grasses for baskets and mats (such as, Carex obnupta and Scirpus pungens) causes fog. The fisherman were always getting annoyed with the women who harvested these materials, because they were always making it foggy. It is said that Hesaquiat men shaved with this grass because the edges are so sharp. There is a saying in Hesaquiat which means you're just like citapt, (Carex obnupta) you never change, because citapt is always the same and never seems to change in appearance.

Erosion Control: Carex obnupta provides erosion control and streambank stabilization. The dense swards of slough sedge provide sediment retention and nutrient uptake, thus contributing to water quality improvement. Emergent wetland plant communities dominated by slough sedge provide the following hydrologic functions: maintaining river or stream meander patterns; providing a broad, shallow plain where streamflow velocities slow and sediment deposition occurs; stormwater abatement; a mixing zone where brackish and freshwaters meet; and nutrient-rich habitat for aquatic organisms, fish, waterfowl, and predators such as otter, bald eagles, herons, and raccoons to feed.

Wildlife: The lens-shaped seeds of sedges are eaten by many kinds of wildlife. Birds known to eat sedge seeds include coots, ducks (such as wood ducks, canvasbacks, mallards, pintails, teal, shoveler), marsh birds and shorebirds (dowichers, rails, and sandpipers), upland gamebirds (grouse, pheasant, and wild turkey), and songbirds (house finch, junco, sparrow, and towhee). Waterfowl and ducks eat sedge seeds frequently in small to fair amounts. In addition to providing food for many wildlife species, sedges are also valuable for cover. Frequently they provide nesting cover for ducks, and their tufted growth furnishes concealment and bedding for other animals. Beavers, otters, muskrats and minks make their way through the sedges as they go to and from the water.

Invasive Potential: This plant is densely rhizomatous, and can be invasive in pastures or wet meadows.

Description General: Sedge Family (Cyperaceae). Slough sedge is a robust sedge that grows 60-150 cm tall; this densely tufted, grasslike plant has stout, creeping rhizomes. The leaves are w-shaped, coarse, with the margins rolled under. The 4-8 cylindrical flower spikes are very large and long (5-12 cm) and loosely aggregated at the tip. Carex lyngbyei is a similar species.

Distribution For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. Slough sedge is a coastal plant growing from San Luis County in California north through Oregon and Washington to British Columbia. Slough sedge occurs at elevations below 900 m.

Establishment Adaptation: Slough sedge is an obligate wetland species that prefers fresh water. It grows in wet, shallow, inundated woods, meadows, roadside ditches, coastal swamps, lakeshores, bogs, marshes, and riverbanks. In muddy areas it can grow as a dense, single-species stand. It often grows in association with skunk cabbage (Lysichiton americanum). Slough sedge is very similar to Lyngbye's sedge in growth form and appearance. Both species tolerate brackish often saline coastal wetland areas; they often grow in similar habitats where saltwater and freshwater meet, such as

General Characteristics

General: Sedge Family (Cyperaceae). Slough sedge is a robust sedge that grows 60-150 cm tall; this densely tufted, grasslike plant has stout, creeping rhizomes. The leaves are w-shaped, coarse, with the margins rolled under. The 4-8 cylindrical flower spikes are very large and long (5-12 cm) and loosely aggregated at the tip. Carex lyngbyei is a similar species.

Required Growing Conditions

For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. Slough sedge is a coastal plant growing from San Luis County in California north through Oregon and Washington to British Columbia. Slough sedge occurs at elevations below 900 m.

Cultivation and Care

Adaptation: Slough sedge is an obligate wetland species that prefers fresh water. It grows in wet, shallow, inundated woods, meadows, roadside ditches, coastal swamps, lakeshores, bogs, marshes, and riverbanks. In muddy areas it can grow as a dense, single-species stand. It often grows in association with skunk cabbage (Lysichiton americanum). Slough sedge is very similar to Lyngbye's sedge in growth form and appearance. Both species tolerate brackish often saline coastal wetland areas; they often grow in similar habitats where saltwater and freshwater meet, such as at the mouths of rivers entering the Pacific Ocean, lagoons, or the Puget Sound.

General: Carex obnupta may be planted from bare root stock, seedlings from container stalk, or directly seeded into the soil. Bare root stock or seedlings are preferred revegetation methods, particularly in areas with moving water. Since slough sedge often grows in areas that are hydrologically quite dynamic, with both tidal and fluvial influences, bare root stock plantings are generally recommended. Seeds generally wash away in these conditions. Also, plants started from seeds tend to stay diminutive for over a year, with plant leaves remaining stunted and fragile for a considerable period of time.

Live Plant Collections: Live plant collections are appropriate only under a very limited set of conditions. Loss of wetland ecosystems exceeds 50% in most states and estuarine wetland losses have been as high as 90%. Public lands that allow plant collections, require permits. Permission from the landowner must be acquired to collect on private lands. No more than 1/4 of the plants in an area should be collected; a depth of 15 cm (6 in) is sufficiently deep enough for digging plugs. This will leave enough plants and roots to grow back during the growing season.

Live transplants should be planted as soon as possible. Plants should be transported and stored in a cool location prior to planting. Plugs may be split into smaller units, generally no smaller than 6 x 6 cm (2.4 x 2.4 in) with healthy rhizomes and tops. Weeds in the plugs should be removed by hand. For ease in transport, soil may be washed gently from roots. The roots should always remain moist or in water until planted.

Clip leaves and stem from 15 to 25 cm (6 to 10 inches); this allows the plant to allocate more energy into root production and makes plants easier to handle (the leaves can be sharp). Planting densities of approximately 1 meter centers provide full coverage the first year (given good site conditions). If there is flowing water, increase planting densities to 1/2-meter centers. Plant densities should also be increased with fine soils such as clay or silt, steep slopes or prolonged inundation.

Ideally, plants should be planted in fall just after the first rains, depending on the climate and geographic location. This enables plant root systems to become established before heavy flooding and winter dormancy occurs. Planting survival is highest when plants are dormant, temperatures are cool, and soils are moist. Plants usually need to be planted by hand, as soils are too moist to use machines.

In some areas, winter storms and high tides would wash away newly transplanted seedlings. While in other areas, avoiding high tides and high floods is recommended, because this combination will minimize plant survival. Planting in the spring after high floods may be warranted in this situation.

Seed Germination Seeds usually have to be harvested by hand, as Carex obnupta Bailey grows in very wet habitats that are inaccessible by machine. Carex obnupta Bailey blooms from April to July. Collect seeds when they are ripe, from July to September. Make sure seed heads are full. Plant cleaned seeds in fall. Plant seeds in clean, weed free, moist seed bed. Broadcast seeds and roll in or rake 1/4 to 1/2 beneath the soil surface. Hold off watering so seeds doesn't float out. Some seeds may be l

General Upkeep and Control

The leaves of slough sedge are cut in late summer (August) (Turner et al. 1983). A knife was used to cut the plant at the base as low to the ground as possible. The best plants were said to be those growing in 10 cm (4) of water. The cluster of leaves are cut off or pulled from the tender white bases, where they break off at or just below the ground level. Only the non-flowering, vegetative plants, called the female plants, were gathered.

The harvested sedge leaves are bundled and taken home, where they are sorted according to size; the longest ones, considered the best, were put together and dried. After the leaves have dried slightly, they are split exactly in half lengthwise, from bottom to top, using the thumbnail. After being split, the leaves are dried completely and bleached in the sun. They can then be bundled or stored.

Traditional Resource Management: Conservation practices include the following: 1) gathering only during late summer after seeds are produced; 2) gathering only infertile shoots without flowering stalks; 3) weeding out competing species and removing impediments to growth such a stones and branches; 4) pruning shoots causes sedges to retranslocate nutrients belowground, providing a nutrient reserve to stimulate new growth the following growing season; 5) removal of long, dense shoots provides good opportunities for seedling establishment and recruitment; 6) harvesting aboveground biomass maintains the sedge clone in juvenile and mature life stages, removing decadent old portions of plants and stimulating new growth; and 7) ownership of sedge beds provides the basis for careful tending and sustainable yield of valued resources.

Plant Basics
Category
Growth Rate Rapid
General Type Graminoid
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Moderate
Plant Nativity Native to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Mid Spring
Displays Fall Colors No
Shape/Growth Form Rhizomatous
Drought Tolerance Low
Shade Tolerance Intermediate
Height When Mature 3
Vegetative Spread Moderate
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Spring Summer
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Seed, Sprigs
Moisture Requirements High
Cold Stratification Required No
Minimum Temperature -3
Soil Depth for Roots 12
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Moderate
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.5–7 pH
Precipitation Range 40–40 inches/yr
Planting Density 3450–4800 indiv./acre
Soil Textures Fine, Medium
Soil Depth for Roots 12
Minimum Frost-Free Days 60 day(s)
Salinity Tolerance Medium
CaCO3 Tolerance Medium
Sustainability & Use
Leaf Retention No
Palatability Medium
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database, plants.usda.gov.
National Plant Data Center, Baton Rouge, LA 70874-4490 USA