Eriophorum vaginatum

Sheathed Cottonsedge

Sheathed Cottonsedge, Photo Courtesy USDA Plants Database

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The natural history of the northwoods


  • Eriophorum, from the Greek, 'erion (erion), "wool", and forew (phoreo), "to bring or carry"; hence, "wool bearing"
  • vaginatum, from the Latin vagina, "a covering, sheath", and atus, "possessive of or likeness of something"; hence, "sheathed"
  • Common Name, from
  • Other common names include: Cottonsedge, Cottongrass, Tussock Cottongrass, Hare's Tail, Hare's-tail Grass, Hare's-tail Cottongrass, Hare’s-tail Rush, Single-headed Cottongrass, Tuvull, Hadd, Slidstarr, Tuvdun, Tuv-ängsull (Swe), Torvull (Nor), Tue-Kæruld (Dan), Tupasvilla (Fin), Scheiden-Wollgras (Ger), Hüvelyes gyapjúsás (Hun), Sìoda Monaidh (Gaelic), Tupp-villpea, mustapea, valgepea, sootups, ilvespea (Est), Páperník Pošvatý (Slovak)


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Liliopsida, the Monocotyledons
      • Subclass Commelinidae
        • Order Cyperales
          • Family Cyperaceae, the Sedges
            • Genus Eriophorum, the Cotton Sedges
  • Taxonomic Serial Number: 40104
  • Also known as Eriophorum spissum, Eriophorum callitrix, Scirpus faurieri


  • A native, tussock-forming sedge.
  • ¼, ½, ¾, º, é
  • Leaves acaulescent; scales tightly compacted. Foliage dies back each winter, but basal portions of leaves and stems remain green.
  • Stem 8"-28" long and sheathed to half its length.
  • Roots densely fibrous, dying back to rootstocks each winter. The roots hydrolyze and absorb organic phosphorus compounds from the soil, providing up to 69% of the plant's phosphorus requirement.
  • Flower a densely tufted cyme of multiflowered spikelets.
    • Sepals
    • Petals
    • Stamens
    • Pistils
    • Ovary superior (within blossom) inferior (below flower)
  • Fruit an achene.
  • Seed
  • Tussocks composed of 300-600 individual tillers. They are elevated above ground level. Individual tillers live less than 8 years; estimated age of mature tussocks ranges from 122 to 187 years.


  • Unmistakable in bloom as a Cotton Sedge.
  • Identifiable as
  • Distinguished from
  • Field Marks


  • Circumboreal; Alaska to Labrador and south to Minnesota, Wisconsin, Indiana, and Pennsylvania.


  • Tundra bogs, muskegs, and pockets of boreal forest.
  • Parent materials of supporting soils include polymictic conglomerate, lithic wacke, siltstone, and shale overlain by frozen glacial till and sand or sandy loam. Mineral soil is usually covered by an up to 16" thick horizon of poorly decomposed peat. The superficial surface layer may be a hepatic, moss, or lichen mat. Soils are well to poorly drained, low in nutrients, and acidic.
  • Colonizes disturbed sites including burns. Tussock communities are stable for many decades, but are eventually replaced in the absence of disturbance. In the Lake States, it is replaced by Tamarack (Larix laricina) and Red Pine (Pinus resinosa). Also grows in open conifer swamps dominated by Black Spruce (Picea mariana) and/or Tamarack (Larix laricina).
  • Survives fire because its growing points are insulated by tightly bunched dead and live tillers, stem sheaths, and scales. The elevated position of tussocks increases resistance to ground fire. Fire provides an opportunity for seedling establishment. Since sheathed cottonsedge has both shallowly and deeply buried seed, some viable seed is available regardless of depth of burn into the peat horizon. Burned peat is an ideal seedbed. Light- to moderate-severity fire generally top-kills sheathed cottonsedge. Severe fire may kill tussocks Sheathed cottonsedge sprouts from burned tillers and establishes from seed following fire. Flower and tiller production increase after top-kill.
  • Flower buds are formed the year prior to flowering.


  • Trees: Tamarack (Larix laricina), Black Spruce (Picea mariana), Red Pine (Pinus resinosa)
  • Shrubs: Bog Rosemary (Andromeda glaucophylla), Bog Birch (Betula pumila), Leatherleaf (Chamaedaphne calyculata), Bog Laurel (Kalmia polifolia),
  • Herbs: Few-Seeded Sedge (Carex oligosperma)
  • Ground Covers: Sphagnum mosses
  • Mammals: Grazed by sheep, cattle, lemmings, ground squirrels, caribou, and geese. Caribou graze it year-round; it may form a considerable portion of their diet in some areas.
  • Birds: Open muskeg-sheathed cottonsedge tussock areas in the Lake States are preferred habitat of sharp-tailed grouse. Waterfowl use these areas as breeding grounds


  • Although the cottony heads were collected in parts of Scotland to be used for wound dressings during the First World War, the fibres are too short to be of any commercial use.



  • Reproduces sexually by seed and vegetatively by tillering.
  • Seeds are first produced at age 3 and are dispersed by wind. Flower and seed production increase with disturbance. Seeds readily germinate after overwintering when exposed to light and warm temperatures. Live mosses or liverworts, dead leaves, and dead peat are favorable seedbeds.
  • Seedling establishment is best on disturbed sites; rare in mature tussock communities. Seedling growth is largely controlled by nutrient availability and is most rapid after fire has released nutrients into the soil.
  • Produces tillers at the rate of one to three per year, with tillering increasing in response to disturbance. Tillers die after flowering but decompose slowly due to compaction and low temperature.


  • By division


  • Hardy to USDA Zone 2 (average minimum annual temperature -50ºF)
  • Cultural Requirements
    • Sun
    • Soil
    • Water
    • Spacing
    • Fertilization
  • Size 12"-18"W x 12"-18"H
  • Growth rate
  • Good for
  • Available by mail order from specialty suppliers or at local nurseries



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Last updated on 26 February, 2004