War on Weeds — Weeds are Everybody’s Problem

Shepherd’s purse

Shepherd’s purse (Capsella bursa-pastoris) is a winter annual native to Europe. It invades roadsides, pastures, gardens, cultivated fields and other disturbed sites. Shepherd’s purse is widely established in Idaho and surrounding areas. It is a prolific seed producer; a single plant can produce up to 40,000 seeds in a single year. Seeds can remain viable for up to 35 years.

Shepherd’s purse grows 3 to 18 inches tall depending on soil fertility, precipitation and other factors. Soon after seeds germinate a basal rosette is formed, from which flowering stalks grow. Rosette leaves are deeply lobed, while upper leaves are smaller and smooth or slightly toothed. Small white flowers are formed at the top of the plant. As flowers mature small heart shaped seed pods are produced. Flowers continue to form at the top of the plant throughout the season.

Integrated Pest Management (IPM) options

• Prevention — Learn to identify this plant. Clean equipment after leaving an infested area.
• Mechanical — Hand pulling can be effective on small infestations. Fall tillage can help to eliminate rosettes that would overwinter.
• Cultural — Establish a healthy stand of beneficial plants that will compete for essential resources. Using proper grazing management strategies will allow beneficial plants to have an advantage over weeds.
• Chemical — 2,4-D, Glyphosate and Dicamba are all herbicide active ingredients that can effectively control this weed. Apply herbicides to actively growing weeds. Always read and follow herbicide label directions.

Idaho is a wonderful place with awesome natural resources, landscapes, agriculture and recreational opportunities. Weeds threaten all the things that we love about Idaho. To detect, contain and control weeds in Idaho we have declared “War on Weeds.” These short articles are designed to give a brief description of each species, an explanation about why it’s a problem, insights into identification and Integrated Pest Management control options. — Justin Hatch

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• Shepherd's purse, 12-21