Puncturevine, an insidious and noxious plant, poses serious threats to pastures, roadsides, waste places, and cultivated fields. Its woody burr, adorned with sharp and rigid spines, is a menace to both animals and humans, causing injuries to unsuspecting passersby and even damaging bicycle tires and footwear. Although not typically grazed, puncturevine is toxic to livestock, particularly sheep, if ingested in significant quantities. Additionally, it becomes a painful problem for fruit pickers when found in orchards or vineyards.

Identification: This summer annual herb sprawls along the ground, emanating from a simple, woody taproot. Its small, solitary yellow flowers boast five petals, five sepals, and ten stamens, borne on short stalks at leaf nodes. Opposite oblong leaves with short stalks are covered in hair and are pinnately compound, displaying 1/4 inch long leaflets. The numerous hairy stems can extend up to six feet, forming a dense mat. Its notorious fruit, the woody burr, breaks into five sections, each resembling a goat's head.

Habitat: Puncturevine thrives in diverse environments, including pastures, roadsides, waste places, parks, and agricultural areas, extending its invasive presence throughout various regions.

Reproduction: Reproducing solely by seeds, puncturevine germinates primarily between April and October, triggered by favorable conditions such as rainfall or irrigation. A single plant can produce anywhere from 200 to 5,000 seeds, and under certain circumstances, even up to an astounding 100,000 seeds.

Control Measures: Effectively controlling puncturevine requires concerted efforts, as it rapidly spreads through its prodigious seed production. Preventing seed formation by removing plants before seed production becomes paramount. When dealing with infestations, it is crucial to clean shoes, clothing, and tires thoroughly to prevent further seed dispersal to unaffected areas. Employ a combination of control methods, such as hand-pulling, hoeing, or digging up young plants before seed formation. For more mature plants, it is essential to remove all spiny burrs from the ground.

Biological Control: While puncturevine seed weevils have been studied as a potential biological control method, they have proven ineffective in Washington State, failing to provide adequate control.

Herbicide Control: Carefully chosen herbicides can offer effective control of puncturevine. Postemergent products work best on younger plants, making timely treatment imperative. Selective or non-selective herbicides should be chosen based on specific needs and objectives. Always read and adhere to label instructions for proper application rates and timing.

At GardeningZone, we recognize the perils posed by noxious weeds like puncturevine and stand ready to support your weed management efforts. Connect with us today for expert advice and effective solutions to safeguard your green spaces from this invasive menace.