Polytrichum piliferum
bristly haircap moss
Cosmopolitan (temperate and polar regions worldwide)
Overview
Polytrichum piliferum is a small, stiff, cushion- or turf-forming moss of the family Polytrichaceae, with erect, unbranched shoots 0.4-1.2 inches (1-3 cm) tall on wiry reddish stems. The lance-shaped leaves are rigid and spread out when moist but press close to the stem when dry, each ending in a long, silvery, toothless hair-point that makes dry patches look frosted or greyish. Inner leaf surfaces carry rows of green vertical plates (lamellae) that aid water retention and photosynthesis, a feature of the haircap mosses. Male and female parts grow on separate plants; male shoots end in reddish, flower-like rosettes that act as splash cups for sperm, while female plants raise four-angled spore capsules on long, slender stalks. It grows on dry, open, acidic, sandy or gravelly ground, including heaths, dunes, rocky banks, walls, and disturbed mineral soil in full sun. It withstands intense drought and heat by curling its leaves and reviving when rewetted. As a non-flowering plant it has no roots, flowers, or seeds, holding on by rhizoids. It is crowded out where richer soil and taller plants develop.
Native Range
Native to cool and temperate regions worldwide, including Europe, Asia, the Americas, Africa, and Antarctica, growing on dry, acidic, sandy or gravelly ground in open, sunny places.Suggested Uses
Used in moss gardens, green roofs, gravel and sand beds, and rock plantings where a sun- and drought-tolerant moss is wanted on acidic, free-draining surfaces. It suits hot, open spots that defeat most mosses. Cover spreads slowly and pairs with other heath and dune species.How to Identify
Appearance
Colors
Foliage Colors
Bloom Information
As a moss, this species does not flower; it reproduces by spores. Male and female plants are separate, and four-angled capsules ripen mainly in late spring and summer on long stalks. Sperm are splashed between plants by raindrops landing in the cup-shaped male rosettes.
Detailed Descriptions
Foliage Description
green to grey-greenGrowing Conditions
Sun Requirements
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
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
This moss grows in full sun on dry, sharply drained, acidic sand, grit, or thin mineral soil, and depends on open, exposed conditions. It tolerates extreme drought and heat, drying to a curled grey state and reviving after rain, but fails on rich, limy, or shaded ground. No feeding or routine watering is needed, as it takes moisture from rain and dew. It is established by pressing collected turfs or fragments onto bare, firm, acidic substrate. Competition from grasses and taller plants, along with shade and enrichment, causes its decline. Once settled it needs little care beyond keeping the surface open and weed-free.Pruning
Pruning does not apply to this moss. Maintenance is limited to clearing encroaching grasses, litter, and taller plants that would shade the low turf. Detached shoots and fragments can be repositioned to spread a colony.Container Growing
✓ Suitable for container growing