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Polytrichum formosum

bank haircap moss

Polytrichaceae

Europe, Asia, North America (Holarctic)

Container Friendly

Native to North America

SunPart Shade – Full Shade

WaterMedium

Overview

Polytrichum formosum is a tall, upright acrocarpous moss of the family Polytrichaceae, forming loose green turfs of unbranched stems 1-5 inches (2-12 cm) high. The stiff, lance-shaped leaves spread outward when moist and press against the stem when dry; their upper surface carries narrow longitudinal ridges, or lamellae, that increase the photosynthetic area. Unlike most mosses, it has internal conducting strands that move water and food along the stem, allowing it to grow taller than cushion-forming species. Male plants form rosette-like splash cups at their tips, while fertilised female stems raise rectangular, sharply angled spore capsules on long reddish stalks, each capsule capped by a golden, hairy hood. It anchors by rhizoids in acidic, humus-rich soil and has no roots, flowers, or seeds. The moss grows on woodland banks, heaths, and shaded acid ground, spreading slowly into wide patches. It needs steady moisture and cool shade, thinning and browning where soil is dry, limy, or sun-baked. Old stems persist below the green tips, building a deep, springy layer over time.

Native Range

Native across Europe, temperate Asia, and North America, with a broad Holarctic distribution on acidic soils. It grows on woodland banks, heathland, moorland, and shaded hillsides, common in cool, humid regions.

Suggested Uses

Grown in woodland and shade gardens, moss gardens, and terrariums as a tall, textured green carpet on acidic ground. It suits naturalistic plantings under trees and on shaded banks where grass grows poorly. The deep turfs hold soil on slopes and add winter greenery to shaded beds.

How to Identify

Look for tall, upright, dark green moss stems forming open turfs, with stiff leaves that spread star-like when wet and hug the stem when dry. A hand lens shows narrow green ridges running along the upper leaf surface, a feature of the haircap mosses. The rectangular, sharply four- to six-angled spore capsules on long red stalks, topped by a golden hairy hood, separate Polytrichum formosum from rounder-capsuled relatives.

Appearance

Size & Dimensions

Height1" - 5"

Width/Spread4" - 1'

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Detailed Descriptions

Foliage Description

dark green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-5 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 - 6.0(Acidic)

357912

Soil Types

loam peat sand

Drainagemoist

Water & Climate

Water Needs

Medium

Care & Maintenance

Care Guide

Growth is strongest in cool, shaded, consistently moist conditions on acidic, humus-rich soil, such as woodland floors and shaded banks. The moss takes up water across its leaves and through internal strands, so it depends on humidity and a damp rooting layer. In dry or sunny spots the leaves curl and brown, recovering after rain but growing slowly. Limy soils and deep drought both check it. In cultivation it is grown from transplanted turfs or scattered fragments pressed onto bare acid soil and kept damp and shaded until established. It needs no feeding and no winter protection, staying green through cold weather.