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Eriophorum angustifolium

common cottongrass

Cyperaceae

Circumboreal - Europe, Asia, and North America

Deer Resistant

Native to North America

SunFull Sun – Part Shade

WaterHigh

HardinessZones 2–7

Overview

Eriophorum angustifolium is a rhizomatous perennial sedge forming loose colonies 20-60 cm (8-24 in) tall, with flowering stems reaching 70 cm (28 in). The slender, grass-like leaves are 2-6 mm (0.08-0.24 in) wide, channelled and three-angled toward the tip, and turn bronze in autumn before dying back. Creeping rhizomes spread through saturated peat, so plants build into open stands rather than tight clumps. In late spring each stem carries a nodding cluster of two to seven flower spikelets; after pollination the perianth bristles elongate into the dense white cottony heads that persist into summer and release seed on the wind. It grows in acidic bogs, fens, wet heath, and pond margins where the water table stays at or near the surface year-round. The species tolerates nutrient-poor, permanently waterlogged ground that excludes most plants, but it fails on dry or limey soils and does not persist if its site drains. The foliage has little structure once the cotton heads shed, leaving low green growth for the rest of the season.

Native Range

Eriophorum angustifolium has a circumboreal range across the cool temperate and arctic zones of Europe, Asia, and North America. In North America it occurs across Canada, Alaska, and the northern United States. It occupies bogs and wet tundra from sea level to mountain elevations.

Suggested Uses

Eriophorum angustifolium is planted at pond and lake margins, in bog gardens, and in rain gardens with permanently wet, acidic soil. It is used in wetland restoration and naturalistic peatland plantings. The white summer heads read at a distance in massed, open stands.

How to Identify

Identify it by the nodding cluster of several cottony heads on each stem, unlike the single terminal head of E. vaginatum. The leaf blades are channelled and 2-6 mm (0.08-0.24 in) wide, tapering to a three-angled tip, and the stems are roughly circular in cross-section. Spreading rhizomes produce scattered shoots rather than dense tussocks.

Appearance

Size & Dimensions

Height8" - 2'4"

Width/Spread1' - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Spring Summer

Flowering spikelets appear from April to June, brownish and inconspicuous at first. As seed sets, the perianth bristles lengthen into white cottony tufts 2-4 cm (0.8-1.6 in) long carried through June and July. The cotton heads break up and blow away as the seed ripens.

Detailed Descriptions

Flower Description

white cottony fruiting heads, brown spikelets

Foliage Description

green, turning bronze in autumn

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range3.5 - 5.5(Acidic)

357912

Soil Types

peat loam

Drainagewet

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Grow in full sun on permanently moist to waterlogged, acidic soil such as peat or boggy loam; pond and stream margins and bog gardens suit it. The water table should stay at or just below the surface, as the plant declines if the ground dries. It tolerates nutrient-poor conditions and hard frost across cool temperate and subarctic zones. Lime-rich or free-draining soils are unsuitable. Established stands spread by rhizome and need room or a contained planting pocket. No feeding is required on natural peat.

Pruning

Old foliage can be cut back to the base in late winter before new growth begins. Spent cotton heads are removed where self-seeding is unwanted, though wind disperses most seed quickly. No other routine cutting is needed.