Overview
Bidens pilosa is an erect annual herb 0.3-1.5 m (12-59 in) tall with branching, four-angled stems and opposite leaves divided into three to five toothed leaflets. Small flower heads about 1 cm (0.4 in) across have a yellow centre of disc florets, sometimes ringed by a few short white ray florets. The heads are followed by clusters of narrow black seeds 6-12 mm (0.2-0.5 in) long, each tipped with two to three barbed bristles that cling to clothing, fur, and feathers, which is how the plant spreads. Originally from tropical America, it is now naturalised as a common weed of gardens, crops, roadsides, and disturbed ground across warm regions of Australia and much of the world. It germinates and matures quickly, setting large amounts of seed, so it establishes fast and is difficult to remove once seeding. Young leaves are eaten as a cooked green in several cultures.
Native Range
Native to tropical America. It is now naturalised as a widespread weed across warm-temperate and tropical regions of Australia and much of the world.Suggested Uses
Sometimes grown as an edible leafy green or as a nectar source for pollinators in warm-climate gardens. More often it appears as a volunteer weed of cultivated and disturbed ground. The young shoots are used as a cooked vegetable in parts of Africa and Asia.How to Identify
Appearance
Size & Dimensions
Height1' - 4'11"
Width/Spread8" - 2'
Bloom Information
Small yellow-centred flower heads, sometimes with short white rays, open over a long season in the warmer months and almost year-round in frost-free areas. The flowers draw bees, hoverflies, and butterflies. Clusters of barbed black seeds follow and attach to passing animals and clothing.
Detailed Descriptions
Flower Description
yellow with white raysFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 5-9 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
Water & Climate
Water Needs
Care & Maintenance
Care Guide
Grows in full sun to light shade on almost any soil across a pH range of about 5.0-7.5, tolerating poor, disturbed, and compacted ground. It germinates quickly in warm, moist conditions and grows fast with minimal care. Regular moisture produces lush growth, but the plant also withstands dry spells once rooted. As a frost-tender annual it is killed by cold, completing its life cycle in a single warm season. Removing plants before the seeds form is the main way to limit its rapid spread.Pruning
Pinching the growing tips produces a bushier plant, though it is rarely cultivated deliberately. Removing flower heads before seed sets prevents spread. The plant is otherwise pulled out whole at the end of the season.Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Direct Sow Timing
spring to summer in warm soil
Days to Maturity
60–90 days
Plant Spacing
12 inches
