Landowners are encouraged to learn to identify puncturevine, and then understand how to control it. Puncturevine forms dense mats along road shoulders, vacant lots, beaches and unpaved parking sites, its stems reaching up to 10 feet (3 metres) in length. The stems are covered by hairy leaves that are divided into six to eight leaflets. Tiny, yellow flowers first appear in late spring or early summer, and spiny seedpods emerge a few weeks later. Each seedpod consists of 5 sections that, at maturity, break into tack-like structures with sharp spines. These sharply pointed seedpods stick painfully in bare feet and flatten bicycle tires. Flowering and seed production typically occurs from mid-June to October.
The best method of controlling puncturevine is to prevent establishment by destroying the first plants found in an area before seeds begin to form. Young puncturevine plants are easily controlled by hoeing, shallow tillage or by carefully hand-pulling plants. If seedpods have not yet developed or are immature (small and green), the plants can be composted. If plants have already matured and the seedpods have ripened (turned brown and easily fall off the plants), plants should be carefully pulled and bagged, then taken to the local landfill. Tipping fees are waived for invasive plant disposal at all landfills operated by the Regional District of Okanagan-Similkameen.
One of the greatest challenges this weed poses is its ability to germinate throughout the summer months; therefore, one treatment at the beginning of summer is not enough. Landowners must be vigilant, checking puncturevine prone sites approximately every three weeks, starting in June and continuing until September. New plants need to be continually destroyed to ensure seeds do not form. It is also important for landowners to be able to recognize puncturevine at an early stage of growth, as this is when it can most easily be controlled, as opposed to when it is large and seedpods have matured.
Like most other weeds, puncturevine prefers areas of disturbed, bare ground. Landowners can help by not providing an opportunity for weeds to grow, as well as by patrolling their properties in the summer and controlling any puncturevine they discover. Areas of soil disturbance should be reduced and re-seeded immediately with a suitable dryland seed mix.
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Okanagan And Similkameen
Invasive Species Society
8703 Palmer Place
Phone: 250.404.0115 Email: OASISS@shaw.ca