Spinulum annotinum (interrupted clubmoss)

Spinulum spp.

bristly clubmoss

Lycopodiaceae

Northern Hemisphere (boreal and cool temperate)

Deer Resistant

Native to North America

SunPart Shade – Full Shade

WaterMedium

HardinessZones 2–6

Overview

Spinulum spp. is a small genus of evergreen clubmosses in the family Lycopodiaceae, native to cool temperate and boreal regions of the Northern Hemisphere. These are low, spore-bearing plants rather than flowering ones. Horizontal stems creep along or just under the ground, sending up unbranched to sparsely branched leafy shoots 4-10 inches (10-25 cm) tall. The small, stiff, needle-like leaves spread out from the shoots and end in a sharp point, giving a bristly look; in S. annotinum the leaves are arranged in distinct annual tiers along the stem. Spores are produced in narrow cones, or strobili, borne singly at the shoot tips in late summer. The genus grows on acidic, humus-rich soils in coniferous and mixed woodland, often among mosses, in cool shade with steady moisture. It spreads slowly and is hard to transplant, since it depends on soil fungi. Foliage stays green through winter.

Native Range

Spinulum spp. is native to the cool temperate and boreal Northern Hemisphere, across North America, Europe, and northern Asia. The clubmosses grow in coniferous and mixed forests, on heaths, and in mossy, acidic ground, from lowland to mountain elevations.

Suggested Uses

Spinulum spp. is rarely cultivated and is encountered mainly in woodland, native, and conservation settings on acidic ground. Where it occurs naturally, it is left in place as a slow-spreading evergreen groundcover among mosses and conifers. It has little use as a planted ornamental.

How to Identify

Recognized by creeping ground stems and upright, bristly leafy shoots 4-10 inches (10-25 cm) tall clothed in stiff, needle-like, sharp-pointed leaves. Narrow spore cones stand singly at the shoot tips rather than on stalks. In S. annotinum the leaves form clear yearly tiers along the stem, which separates it from the stalked-coned clubmosses.

Appearance

Size & Dimensions

Height4" - 10"

Width/Spread1' - 3'

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Spinulum spp. is a clubmoss and does not flower. It reproduces by spores released from narrow cones, or strobili, at the shoot tips, mainly in late summer and autumn. Spores are wind-borne and very slow to develop into new plants.

Detailed Descriptions

Foliage Description

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 - 5.5(Acidic)

357912

Soil Types

peat loam

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

5-10 years

Care & Maintenance

Care Guide

Plants grow in cool, dappled to full shade on moist, acidic, humus-rich soils at a pH from about 4.5 to 5.5. They depend on partnerships with soil fungi, which makes them slow to establish and hard to transplant from the wild. Constant moisture, cool roots, and an undisturbed leaf-litter layer suit them, while heat, drought, and alkaline soils are not tolerated. They are seldom cultivated and spread very slowly by creeping stems. Plants are left undisturbed once settled. Hardiness covers cold-temperate and boreal zones, roughly USDA zones 2 to 6.

Pruning

No pruning is needed or practised. Dead shoots can be cleared by hand if wanted. The creeping stems are left intact, since the plant spreads only slowly and recovers poorly from disturbance.

⚠️ Toxicity Warning

Unknown

Perennial