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Atrichum spp.

smoothcap mosses

Polytrichaceae

Temperate Northern Hemisphere — North America, Europe, and Asia

Deer Resistant Container Friendly

Native to North America

SunPart Shade – Full Shade

WaterHigh

Overview

Atrichum spp. is a genus of about 15 mosses in the family Polytrichaceae, known as smoothcap mosses for the smooth, hairless caps on their spore capsules. Plants form low, spreading turfs of upright shoots 0.4–2.8 inches (1–7 cm) tall, dark green to yellow-green, arising from creeping underground stems. The narrow leaves are strongly undulate, with wavy transverse ridges and toothed margins, and a few low ridges of green tissue run along the midrib. In dry air the leaves twist and curl against the stem, expanding again when moisture returns. The genus is widespread across the temperate Northern Hemisphere, with species in North America, Europe, and Asia, and a few reaching the Southern Hemisphere. Plants grow on bare, moist soil of shaded banks, ditches, woodland paths, and disturbed ground, often on acidic clay. Reproduction is by spores released from cylindrical capsules raised on reddish stalks. Like all mosses, Atrichum spp. lacks true roots and takes up water directly through its surface, so it depends on shade and steady moisture and dries quickly in sun and wind.

Native Range

The genus is widespread across the temperate Northern Hemisphere, with species native to North America, Europe, and Asia, and a few reaching the Southern Hemisphere. Atrichum spp. colonizes bare, moist soil on shaded banks, woodland tracks, ditch sides, and disturbed ground. Acidic clay and loam soils suit most species.

Suggested Uses

Atrichum spp. is grown in moss gardens, as shaded ground cover, and in terrariums, and between stepping stones on damp, shaded paths. The low turfs cover bare soil where grass fails in deep shade. Plants are also used in woodland and Japanese-style garden plantings.

How to Identify

Shoots are upright and unbranched, carrying narrow leaves marked by wavy transverse undulations across the blade. The leaf margins are toothed, and a few low green ridges, or lamellae, run along the midrib, fewer than in the related haircap mosses. When dry the leaves twist and curl, then flatten as they take up water. The smooth, hairless capsule cap separates Atrichum spp. from the hooded capsules of Polytrichum spp..

Appearance

Size & Dimensions

Height1" - 3"

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Atrichum spp. reproduces by spores rather than flowers. Cylindrical spore capsules form on slender reddish stalks, ripening through autumn and winter in many species. The capsules shed spores when mature, after which the smooth cap falls away.

Detailed Descriptions

Foliage Description

dark green to yellow-green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Tolerates up to 4 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 Range4.5 - 6.5(Acidic)

357912

Soil Types

clay loam peat

Drainagemoist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Plants grow in partial to full shade on moist, acidic soil, and scorch in direct sun and dry air. Steady surface moisture is needed, as the shoots absorb water directly and have no roots to draw on reserves. Bare, compacted clay or loam suits establishment more than loose, rich soil. Foot traffic and competing weeds set back the low turfs, so a cleared, shaded site favors steady growth. Misting during dry spells keeps the shoots green and growing.

Pruning

Atrichum spp. needs no pruning. Fallen leaves and debris are cleared from the surface so light reaches the low shoots. Torn or dried patches recover as moisture returns and new shoots spread from the creeping stems.