Grimmia pulvinata (Grey-cushioned Grimmia)

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Grimmia pulvinata

grey-cushioned grimmia

Grimmiaceae

Cosmopolitan (temperate regions worldwide)

Drought Tolerant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterVery Low · drought-tolerant

Overview

Grimmia pulvinata is a small acrocarpous moss of the family Grimmiaceae that grows in neat, rounded, grey-green cushions on hard calcareous surfaces such as limestone, concrete, mortar, walls, and roof tiles. Each cushion measures roughly 0.4-1.2 inches (1-3 cm) across, built from densely packed shoots whose leaves end in long, silvery hair-points that give the colony a hoary, frosted look. The curved spore stalks bend back so the developing capsules are drawn down into the cushion, then straighten as the capsules ripen and shed spores. It has no roots, flowers, or seeds, anchoring by rhizoids and tolerating extreme drying by suspending growth until moisture returns. The moss occupies sun-baked, nutrient-poor stone where few plants persist, and grows slowly, with cushions enlarging over several years. It browns and curls in prolonged drought, the white hair-points reflecting light and reducing water loss, and greens within minutes of rainfall. Heavy shade, acidic substrates, and constant wetness all limit it, restricting the moss to open, well-drained, base-rich stonework.

Native Range

Cosmopolitan in distribution, occurring through Europe, Asia, North Africa, the Americas, and Australasia on natural limestone outcrops and on man-made stone and concrete. It is a familiar cushion moss of urban walls and monuments in temperate regions.

Suggested Uses

Grown on rock features, stone troughs, tufa, and lime-mortared walls in moss gardens and alpine displays where a tight, silvery cushion texture is wanted on sunny stone. It establishes on concrete ornaments, paving, and roofing as a weathering, aged finish. In green-roof and wall plantings it occupies hot, dry stonework that other mosses cannot hold.

How to Identify

Look for compact, rounded grey-green to silvery cushions, typically 0.4-1.2 inches (1-3 cm) wide, sitting on limestone, mortar, or concrete in full sun. The grey cast comes from long glassy hair-points at the leaf tips, visible with a hand lens. When moist, curved spore stalks bend the young capsules back into the cushion, a feature separating Grimmia pulvinata from flat-growing stone mosses.

Appearance

Size & Dimensions

Height1" - 2"

Width/Spread1" - 4"

Colors

Foliage Colors

grey green

silver

Fall Foliage Colors

no change

Detailed Descriptions

Foliage Description

grey-green with silvery hair-points

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 Range6.5 - 8.5(Alkaline)

357912

Soil Types

rocky chalk

Drainagedry

Water & Climate

Water Needs

Very Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Growth occurs on hard, base-rich surfaces in full sun, including limestone, concrete, mortar joints, and clay roof tiles, with no soil required. The moss absorbs water and minerals directly from rain and dust across its shoots and endures long dry spells by drying out completely and reviving when wet. It needs no feeding, watering, or winter protection, drawing entirely on rainfall. Dense shade and continuous moisture suppress it, as do strongly acidic substrates. In cultivation it is established by pressing cushion fragments onto damp lime mortar or porous stone and keeping them lightly moist until anchored. Once attached, the colony maintains itself with no further care.