Practical ecological knowledge for the temperate reader.

Eriophorum Sp. - Cotton Grass

Family: Cyperaceae - Sedge Family [E-flora]

"Perennial herb, erect. Stem: cylindric, solid. Leaf: basal and cauline; ligule present; blade ± scabrous on keel or angles. Inflorescence: 1, terminal, ± umbel-like [head-like or spikelet 1]; inflorescence bracts 1–several, leaf- or scale-like; spikelets several [1]; flower bracts spiraled, > 10, ovate, membranous, glabrous, tip entire. Flower: bisexual; perianth bristles 10–25, >> fruit, generally > flower bracts, >> flower bracts in fruit, ± straight, barbs 0; stamens 3; style 3-branched. Fruit: 3-sided, ± flat.
± 25 species: northern temperate. (Greek: wool-bearing) Eriophorum crinigerum moved to Calliscirpus (Gilmour et al. 2013); see note under family." [Jepson]

"Cotton grasses favor wet bogs, roadsides, and tundra. There are over one dozen Eriophorum species and subspecies distributed throughout Alaska alone. Distribution decreases markedly in the southern range of the Pacific Northwest. Only one species, E. gracile, reaches from Alaska to California." [Schofield]

Local Species;

  1. Eriophorum angustifolium - Narrow-leaved cotton-grass [E-flora]
  2. Eriophorum chamissonis - Chamisso's cotton-grass [E-flora][PCBC2004]
  3. Eriophorum gracile - Slender cotton-grass [E-flora]
  4. Eriophorum virginicum - Tawny cotton-grass [E-flora]



"Sedge family members should not be used medicinally without medical supervision. Properties and effectiveness are variable with species." [Schofield]

Edible Uses

Other Uses

Medicinal Uses


"Moist tundra occupies the foothills and lower elevations of the Alaska Range as well as extensive areas on the Seward and Alaska peninsulas, the Aleutian Islands, and the islands of the Bering Sea. The type varies from almost continuous and uniformly developed cottongrass (Eriophorum) tussocks with sparse growth of other sedges and dwarf shrubs to stands where tussocks are scarce or lacking and dwarf shrubs are dominant. Over wide areas in Arctic Alaska, the cottongrass tussock type is the most widespread of all vegetation types." [Viereck ATS]


Eriophorum angustifolium - Narrow-leaved cotton-grass

"Eriophorum angustifolium is a PERENNIAL growing to 0.6 m (2ft) by 1 m (3ft 3in). It is hardy to zone (UK) 4 and is not frost tender. It is in flower from May to June, and the seeds ripen from Jul to August. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and can grow in heavy clay soil. Suitable pH: acid soils and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers wet soil and can grow in water." [PFAF]

"General: Perennial herb from creeping rhizomes; stems 10-90 cm tall." [IFBC-E-flora]
"Leaves: Sheaths brownish to purplish or blackish, persistent; blades 2-6 (8) mm wide, flat but becoming narrow and folded toward the tips, the uppermost ones equalling or exceeding the sheaths." [IFBC-E-flora]
"Flowers: Spikes 2 to 10, terminal, erect, at least some of them pendulous, egg-shaped and 1-2 cm long in flower, 2-4 cm long in fruit; anthers 2.5-4 mm long; involucral bracts several, unequal, 2 or more of them evidently leaflike, the longest ones equalling or surpassing the inflorescence." [IFBC-E-flora]
"Fruits: Scales brownish or blackish-green, egg-shaped to lanceolate, appressed to ascending, 1-ribbed, pointed, the slender midribs not reaching the tips; perianth bristles numerous, whitish, creamy-white to tawny, many times longer than the achenes; achenes blackish, 2-3 mm long, broadly lanceolate to egg-shaped." [IFBC-E-flora]

"Habitat / Range Bogs, fens, marshes, shorelines and wet meadows in all vegetation zones; common throughout BC; circumpolar, N to AK, YT and NT, E to NF and S to NH, NC, TN, IA, NE, NM, ID and OR; Eurasia." [IFBC-E-flora]

Origin Status: Native [E-flora]

"Ecological Indicator Information A very shade-intolerant, submontane to subalpine, circumpolar sedge (transcontinental in North America). Occurs on wet to very wet, nitrogen-poor soils (Mor humus forms) within boreal, cool temperate, and cool mesothermal climates. Common in semi-terrestrial communities on water-collecting sites (peat bogs). Associated with Kalmia occidentalis, Ledum groenlandicum, Sphagnum species, and Trientalis arctica. An oxylophytic species characteristic of nutrient-poor wetlands." (Information applies to coastal locations only) [IPBC-E-flora]

Edible Uses

Other Uses

Medicinal Uses

"The leaves and roots are considerably astringent and have been used in the past as a treatment for diarrhoea[4]. Some native North American Indian tribes would eat the stems raw in order to restore good health to people in generally poor health[257]." [PFAF]

"But cottongrass heads were a crop on the Isle of Skye, gathered usually by the children. Dried, they were used to stuff pillows and quilts (Swire. 1961) (St Bride lined the bed of Christ with cotton-grass, even though the birth of Christ occurred in mid-winter (Swire. 1964)). Stuffing pillows must have been a tedious task, for when the heads were used whole they would be lumpy in a pillow, but the trick is to remove the tough base and use only the down. It can be spun like cotton, but the fibres are more brittle than those of cotton, so not so useful. Candle and lamp wicks used to be made of the down (Johnson), while children often use them like powder puffs (Bairacli-Levy)." [DPL Watts]

"Requires boggy conditions or a pond margin and an acid soil[1, 162]. Grows well in heavy clay soils. Quite invasive." [PFAF]

"Seed - sow in situ in spring in a moist soil in light shade. Germination usually takes place within 2 - 6 weeks at 15oc[200]. If the seed is in short supply it can be sown in pots in a cold frame. Place the pots in a try of water to keep the compost moist. When large enough to handle, prick the seedlings out into individual pots and plant them out in the summer. Division in spring or autumn. Very easy, the divisions can be replanted direct into their permanent positions." [PFAF]

"The high annual rainfall and cold winters at the higher latitudes also favor perennial cool season grasses and sedges over some of the annual species that occur farther south. The acidic conditions may also be augmented by accumulations of sphagnum moss on the bog surface. Plants include round leaf sundew (Drosera rotundifolia), cottongrass (Eriophorum spp.), cloudberry (Rubus chamaemorus), bog laurel (Andromeda polifolia), bog bean (Menyanthes trifoliate), and Cusick’s sedge (Carex cusickii)." [Apostol RPNW]

Arsenic Hyperaccumulator: "Accumulator plants uptake and translocate arsenic to shoots without toxic symptoms (Ross and Kaye 1994; Prasad 2008) . Mention has been made of “root accumulators”, which have higher arsenic concentration in roots than in shoots, Carex rostrata, Eriophorum angustifolium, Phragmites australis, and Salix sp (Stoltz and Greger 2002a, b, 2006a, b, c) and also it has been pointed out that spontaneous vegetation species covered the large toxic mine spill contaminated areas in Spain (Del Rio et al. 2002)." Plants on mine talings yeilded 152 (mg As kg-1 soil) [Lichtfouse ECSW]

Fe Resistance: "The species with the highest resistance were almost exclusively monocots (e.g. Eriophorum angustifolium, Carex echinata), while the most sensitive species were all dicots (e.g. Rumex hydrolapathum, Epilobiumhirsutum). The higher Fe resistance ofmonocots may result from two traits: a more efficient detoxification system which reduces direct Fe toxicity and lower growth rates which minimize indirect toxicity effects on mineral nutrition. Iron resistance and relative growth rates were negatively correlated" [Prasad HMSP]

Eriophorum angustifolium subsp. triste [E-flora]
E. polystachion. [PFAF]


Eriophorum chamissonis - Chamisso's cotton-grass

Subtaxa Present in B.C.

"General: Perennial herb from creeping rhizomes or stolons, extensively colonial; stem 20-75 cm tall." [IFBC-E-flora]

"Leaves: Basal sheaths brown to purplish-brown, cross-wrinkled, persistent, not or only somewhat expanded upwards, the uppermost sheaths usually bladeless; stem leaves few, usually 1 to 3, located below the middle of the stems, mostly borne near the bases, rarely one above; blades 0.4-2 mm wide, short to elongate, thread-like, folded throughout or triangular in cross-section." [IFBC-E-flora]

"Flowers: Spikes solitary, terminal, erect, at least some of them pendulous, appearing broad-based, egg-shaped-cylindrical and 1.5-2 cm long in flower, globe-shaped and 2-4 cm long in fruit; anthers mostly 1-3 (3.2) mm long; involucral bracts lacking." [IFBC-E-flora]

"Fruits: Scales blackish to greyish, the middle scales lanceolate or broadly lanceolate, appressed to ascending, the midribs not reaching the tips, more or less long and sharp-pointed or blunt, with narrow, pale margins or broad translucent margins, the sterile sc" [IFBC-E-flora]

Notes: Two, sometimes difficult to separate, varieties occur in BC:

"Habitat / Range Bogs, streambanks, lakeshores and wet meadows in all vegetation zones; var. chamissonis – common throughout BC; var. albidum – infrequent in N BC, rare S to 51oN east of the Coast-Cascade Mountains; N to AK, YT and NT, E to NF and S to WI, MN, ND, CO and OR." [IFBC-E-flora]

Status: Native [E-flora]



Eriophorum gracile - Slender cotton-grass

"General: Perennial, loosely tufted or turf-forming herb from slender, much-branched rhizomes; stems arising singly, slender, triangular in cross-section, at least above, (15) 20-60 cm tall." [IFBC-E-flora]

"Leaves: Basal sheaths brownish to reddish-brown, cross-wrinkled, persistent, lacking young basal leaves at flowering time; leaves basal or stem, shorter than the stem, the stem leaves 2 or 3; blades 0.8-1.5 (2) mm wide, elongate, narrow and folded towards the tips or triangular in cross-section, the uppermost leaves with reduced blades usually shorter than the well-developed sheaths." [IFBC-E-flora]

"Flowers: Spikes 2 to 8, terminal, erect, in compact to open, umbrella-like cymes, the stalks slender, unequal, circular in cross-section, tapered, not evidently compressed, minutely stiff short-hairy, egg-shaped and 0.5-1 cm long in flower, 1.5-2 (2.5) cm long in fruit; anthers mostly 1-3 mm long; involucral bracts several but only one of them evidently green and leaflike, usually shorter than the inflorescence, not purplish basally." [IFBC-E-flora]

"Fruits: Scales blackish-green to greenish-brown or greyish, egg-shaped to lanceolate, appressed to ascending, the slender midribs not reaching the tips, blunt; perianth bristles numerous, white or whitish, many times longer than the achenes; achenes straw-coloured or light brown, 2.5-3.5 mm long, narrowly egg-shaped to narrowly lanceolate." [IFBC-E-flora]

"Habitat / Range Bogs, marshes and lakeshores in the lowland, steppe and montane zones; infrequent in BC, absent from NW BC, Queen Charlotte Islands and Vancouver Island; circumpolar, N to AK and NT, E to NF and S to ME, MA, PA, IN, IL, IA, NE, CO, ID and CA; Eurasia." [IFBC-E-flora]"W.D.J. Koch ex Roth, Slender Cottongrass. Bogs and open swamps. Circumboreal, in North America from NL (Labrador) west to AK, south to s. PA (Rhoads & Klein 1993), s.NJ, w. MD (C. Frye, pers comm. 2000), DE (McAvoy & Bennett 2001), OH, IN, IL, MN, CO, UT, NV, and CA." [Weakley FSMAS]

Status: Native [E-flora]


Eriophorum virginicum - Tawny cotton-grass

"Introduction Tawny cotton-grass (a.k.a. tawny bog cotton) is an easily recognized rhizomatous (clonal) species of cotton-grass. Like other species of cotton-grass, it is mostly restricted to peatlands where it can be a prominent component. Eriophorum species in general are boreal in distribution and are mostly circumpolar. The exception is tawny cotton-grass, which is found only in eastern North America from Ontario, Quebec, and Labardor south to the Carolinas. It has been introduced in British Columbia in the Fraser delta, where it can be seen in many delta bogs, including the Lulu Island Bog, Burns Bog, and the Langley Bog. This is a late-flowering species of cotton-grass. As perianth bristles expand in this species they become tawny and brownish. It is anatomically different from other species of cotton-grass. View a video about identifying tawny cotton-grass in the field, with Tony Reznicek." [E-flora]

"General: Perennial herb from rhizomes; stems solitary or few together, stiff, erect, up to 100 cm tall." [IFBC-E-flora]

"Leaves: Sheaths brownish to purplish, persistent; blades 2-4 mm wide, flat, except at the tips." [IFBC-E-flora]

"Flowers: Spikes several, terminal, in crowded clusters, the stalks short and nearly equal; anthers 1-1.5 mm long; involucral bracts 2 (3), unequal, leaflike, the longest greatly surpassing the inflorescence." [IFBC-E-flora]

"Fruits: Scales coppery or brown, blunt or pointed, the midribs prominently 3- to 5-nerved; perianth bristles numerous, tawny or coppery, many times longer than the achenes; achenes 3-3.5 mm long, a third as wide." [IFBC-E-flora]

"Habitat / Range Bogs and wet ditches in the lowland zone; rare in SW BC, known only from the Fraser River delta; introduced from E North America." [IFBC-E-flora]

Status: Exotic [E-flora]


Page last modified on Tuesday, July 13, 2021 9:41 PM