Callicladium spp.

callicladium moss

Hypnaceae

Northern hemisphere temperate and boreal forests

Container Friendly

Native to North America

SunFull Shade – Part Shade

WaterHigh

HardinessZones 3–7

Overview

Callicladium spp. is a genus of pleurocarpous mosses in the family Hypnaceae, growing as flat, spreading mats rather than as upright plants. The commonly recorded species, C. haldanianum, forms glossy yellow-green to golden patches 0.4-1.2 inches (1-3 cm) deep over rotting logs, tree bases, stumps, and humus-rich soil. Slender, irregularly branched stems creep horizontally and carry small, concave, lance-shaped leaves about 0.08 inch (2 mm) long that curve to one side when dry. Like all mosses, the genus has no roots, flowers, or vascular tissue; it takes up water directly over its surface and anchors by thread-like rhizoids. Reproduction is by spores released from cylindrical capsules raised on reddish stalks 0.4-0.8 inch (10-20 mm) tall in late autumn and winter. Callicladium spp. occurs across cool, moist temperate and boreal forest in the northern hemisphere and depends on steady humidity and shade, drying to a duller, contracted mat when conditions turn hot and exposed.

Native Range

Callicladium spp. is distributed through cool temperate and boreal regions of the northern hemisphere, including North America, Europe, and northern Asia. It grows in moist, shaded forest on decaying wood, stumps, log surfaces, tree bases, and peaty or humus-rich soil.

Suggested Uses

Callicladium spp. is used in moss gardens, terrariums, and shaded naturalistic plantings on logs, stumps, and damp ground. It can green over rotting wood and bare humus in cool, shaded settings. Its need for constant moisture and shade rules out open, sunny, or dry sites.

How to Identify

Look for flat, glossy yellow-green to golden mats on rotting logs and stump tops in damp shade. The creeping stems are irregularly branched and clothed in small concave leaves that turn to one side as they dry. Spore capsules are cylindrical and slightly curved, held on reddish stalks about 0.4-0.8 inch (10-20 mm) tall. The glossy sheen and wood-dwelling habit help separate it from duller soil mosses.

Appearance

Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Mosses do not flower. Spore capsules mature mainly in late autumn and winter, releasing spores as the capsule dries and its mouth opens. The genus also spreads vegetatively when detached stem fragments take hold and form new mats.

Detailed Descriptions

Foliage Description

Yellow-green to golden

Growing Conditions

Sun Requirements

SunFull Shade SunPartial Shade

Tolerates up to 2 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

peat

Drainagemoist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

Forms mats within 1-2 seasons

Care & Maintenance

Care Guide

Callicladium spp. is rarely cultivated and is met mainly in woodland on rotting wood, or in moss gardens and terrariums. It needs constant shade, high humidity, and a damp organic surface such as decaying wood or peaty soil, and it browns and contracts in direct sun or dry air. It takes no fertiliser and draws moisture and minerals from rain and surface films rather than from roots. Established mats can be lifted and pressed onto new damp wood or soil to spread them. Slugs and drought are the main causes of patchy loss.

Pruning

No pruning is needed. Mats can be trimmed or torn to shape, and the removed pieces laid on fresh damp substrate to start new growth. Accumulated leaf litter can be lifted off so the mat is not smothered.