Weed of the Week: Shepherd’s-purse

Authors: Michael Denney, Christo Sullivan, Dustin Miller

Description

Shepherd’s-purse, Capsella bursa-pastoris, is a winter annual or biennial plant that reproduces by seed. Seed will typically germinate when soil temperatures are below 60oF in the fall or early spring.

Shep-purse overview BLOG

Shepherd’s-purse first emerges in the form of a rosette.  Base leaves are 3-6” long, about 1.5” wide, and deeply lobed. It is often confused with dandelion. The lower leaf surface has scattered hairs. The rosette overwinters, then resumes growth in the spring. A slender stalk appears and the plant continually bears flowers from spring well into the fall. The flower stalk may be simple or branched, and can grow 6 to 18” tall. The mature seed pods are found on the lower portion and clusters of new flowers can be observed at the tip.  Individual flowers have four white petals that are less than ¼” in size. The leaves on the flower stalk grow 1-2” long and are shaped like arrowheads.

The flat seed pods are about ¼” long, with a notched tip and pointed base. A narrow stem about ½” long attaches each seed pod to the raceme. Seed pods are attached at a 90o angle every ¼ to ½” up the stem. The pods are initially green, then turn to a tan color with two rows of tiny yellow-orange seeds. Each plant produces roughly 30,000-50,000 seeds. Only 1/32” long, seeds are easily scattered by wind or water.Shep-purse seedhead close-up BLOG

Control

Mechanical – Tilling and mowing can be effective if done before flowering occurs.

Chemical – Mustards are resistant to many herbicides, but dicamba or metsulfuron can achieve good control.