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Arctium tomentosum

woolly burdock

Asteraceae Europe and temperate Asia

Attracts Pollinators Attracts Butterflies Drought Tolerant

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 3–9

Overview

Arctium tomentosum is a robust biennial in the daisy family that forms a low leaf rosette in its first year and sends up a branched flowering stem 3-6 feet (0.9-1.8 m) tall in its second. The large heart-shaped lower leaves reach 8-16 inches (20-40 cm) long, green above and densely white-woolly beneath, on hollow grooved stalks. From summer into early fall the stems carry globe-shaped flower heads 0.5-0.75 inch (1.3-2 cm) wide, each holding small purple to pink tubular florets above a ball of hooked green bracts wrapped in cobweb-like woolly hairs, the feature that separates it from the related Arctium minus and Arctium lappa. After flowering the heads dry into burs whose hooked bracts cling to fur, wool, and clothing and carry the seed widely. The plant grows on disturbed ground, roadsides, pastures, and waste places, where the deep taproot and heavy seed set let it spread. The whole plant dies after setting seed. The clinging burs are a nuisance in pet coats and livestock wool, and large stands can crowd other vegetation.

Native Range

Arctium tomentosum is native to Europe and temperate Asia, from the British Isles east across Russia, and has naturalized in North America and other temperate regions as a weed of disturbed land.

Suggested Uses

Rarely planted by choice, it appears mainly as a weed of pastures, roadsides, and disturbed ground. The summer flower heads draw bees and butterflies where the plant is tolerated. The deep taproot is eaten as a vegetable in some cuisines, similar to that of cultivated burdock.

How to Identify

Identify woolly burdock by its large heart-shaped leaves, green above and white-woolly beneath, on a branched stem 3-6 feet (0.9-1.8 m) tall. The globe-shaped flower heads 0.5-0.75 inch (1.3-2 cm) wide carry purple to pink florets above hooked bracts veiled in cobweb-like woolly hairs. The dried burs that follow cling tightly to fur and clothing.

Appearance

Size & Dimensions

Height3' - 6'

Width/Spread2' - 4'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Summer Fall

Flowering occurs from mid summer into early fall, generally July to September in the second year of growth. The branched heads open over several weeks and draw bees and butterflies to the purple florets. As the season ends the heads dry into clinging burs.

Detailed Descriptions

Flower Description

purple to pink

Foliage Description

green above, white-woolly beneath

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 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 Range5.5 - 7.5(Neutral)

357912

Soil Types

clay loam sand

Drainageaverage

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Arctium tomentosum grows in full sun to partial shade on moist, fertile, disturbed soils and tolerates a broad pH range of about 5.5-7.5 and most soil types. It germinates readily and forms a deep taproot in the first year, then flowers and dies in the second. The plant needs no irrigation or fertilizer in average ground and persists in rough, neglected sites. Removing the flower heads before the burs ripen prevents self-seeding and limits spread. Because it self-sows heavily, it can become weedy where left unmanaged. It overwinters as a first-year rosette and is hardy in USDA zones 3-9.

Pruning

Pruning is not part of growing this biennial. Cutting or removing the flowering heads before the burs harden is the main way to stop self-seeding. Whole plants are pulled or cut at the base after they set seed.

✓ Toxicity

Non-toxic