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Arctium lappa

greater burdock

Asteraceae Europe and temperate Asia

Attracts Pollinators Attracts Butterflies Drought Tolerant

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 3–9

Overview

Arctium lappa is a stout biennial that forms a broad rosette of very large leaves in its first year and a branching flowering stalk 3-9 feet (90-300 cm) tall in its second. The lower leaves are heart-shaped and can reach 20-28 inches (50-70 cm) long, dark green above and grey-woolly beneath, on solid, grooved stalks. From mid to late summer of the second year it bears thistle-like flower heads about 1-1.5 inch (2.5-4 cm) across, each a tuft of purple disc florets sitting in a globe of stiff green bracts that end in hooked tips. As the heads dry, these burs catch on fur and clothing and carry the seeds away, the structure that inspired hook-and-loop fastener. A. lappa grows on roadsides, waste ground, ditch banks, and field edges across Europe and Asia and as a naturalised plant in North America. It has a deep, fleshy taproot eaten as a vegetable in East Asia. The plant dies after seeding, and the dry burs can mat the coats of animals.

Native Range

Arctium lappa is native across Europe and temperate Asia, from the British Isles to Japan. It has naturalised widely in North America and other temperate regions, growing in disturbed, nitrogen-rich ground such as roadsides, farmyards, and waste places.

Suggested Uses

Grown in vegetable gardens for its edible taproot, known as gobo, and in herb gardens for traditional medicinal use. It is also kept in wildlife and naturalistic plantings for its bold first-year foliage and late-summer nectar. The burs and large leaves suit informal, rough-ground settings.

How to Identify

Greater burdock is known by its huge, heart-shaped lower leaves with grey-woolly undersides and its purple thistle-like heads enclosed in round clusters of hook-tipped bracts that form clinging burs. The leaf stalks are solid and grooved rather than hollow. A. lappa differs from Arctium minus, lesser burdock, in its larger heads on long stalks and its solid, not hollow, leaf stems.

Appearance

Size & Dimensions

Height3' - 9'

Width/Spread3' - 5'

Reaches mature size in approximately 2 years

Colors

Flower Colors

purple

Foliage Colors

green

Bloom Information

Bloom Period

~10 weeks

Summer

Flowering occurs from July to September in the second year, after which the plant dies. Bees and other insects visit the purple heads through late summer. The bracts harden into burs as the seeds ripen and cling to anything that brushes past well into winter.

Detailed Descriptions

Foliage Description

dark green above, grey beneath

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-12 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 Range5.5 - 7.5(Neutral)

357912

Soil Types

loam clay sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Arctium lappa in full sun to partial shade on deep, moist, fertile soil that lets its long taproot develop, at a neutral to slightly acidic pH. It is hardy through USDA zones 3 to 9 and withstands cold, heat, and poor ground once established. As a biennial it makes leaves the first year and flowers the second, then dies after setting seed. Removing the flower heads before the burs ripen stops self-seeding, which can otherwise be heavy. For edible roots, sow seed in spring and lift the taproot in autumn of the first year before it turns woody. It needs little care beyond water in extended drought.

Pruning

Cut down the flowering stalk before the burs mature to prevent self-seeding and the clinging seed heads. Clear the dead plant after it sets seed at the end of its second year. No other pruning is needed.