Xanthium strumarium

Common Names

Common Cocklebur, Cocklebur, Canada Cocklebur, Rough Cocklebur, Cockleburr, Clotbur, Ditchbur, Large Cocklebur, Donkey Burr

Summary

Cocklebur is an annual herb in the Asteraceae native to the New World and now cosmopolitan, commonly found in open disturbed habitats such as croplands, roadsides, floodplains, and waste areas. It grows as an erect, coarse plant with green stems that may show purple specks; leaves are rough-textured, broad, and heart- or triangular-shaped with toothed margins. It bears monoecious flowers in racemes, with upper parts producing male flowers and lower parts producing female flowers, and develops conspicuous prickly burs that cling to fur, clothing, or wool. Burs contain two seeds, and one seed germinates the next spring while the other may germinate after at least two years, enabling reseeding and colony formation.

It favors disturbed, open sites with sun and moist to wet soils and can rapidly spread as a self-sowing weed, dispersing via burs that attach to animals and clothing. Management considerations include preventing seed production and removing plants before burs develop; traditional uses include medicinal applications and yellow dye from leaves, while seeds may be poisonous to livestock.

Lifecycle

Annual

Height

0.5-6.5 ft

Spread

4-12 inches

Hardiness Zones

Zones 6-9

Sunlight Requirements

Ideally full sun. Tolerates partial sun

Soil Type

No single ideal soil type; tolerates a wide range, with moist, often alkaline, well-drained soils common.

Soil Drainage

Well-drained

Soil pH

6.0-8.0

Bloom Color

Green

Bloom Time

Summer

Foliage Color

Green

Leaf Lifecycle

Deciduous

Growth Rate

Rapid growth

Seasons of Interest

Summer and Fall

Propagation Methods

Seeds

Attracts Wildlife

Birds: seeds eaten by mourning doves (to a limited extent); seeds eaten by purple finch; seeds may disperse via animals