Another member of the mustard family, Shepherd's purse can produce over 33,000 seeds per plant.
The lower leaves are petioled and deeply lobed, quite similar to that of a dandelion. The upper leaves are irregularly toothed and clasping. White flowers appear in clusters at the top of a flowerstalk that can reach 6 to 18 inches in height. The flowers are only about 2mm across. Seeds are contained in silicles that are notched triangles and resemble the purses once carried by shepherds.
Shepherd's purse has a slender taproot and can be easily hand-pulled or hoed from moist soil in flower and vegetable gardens while plants are young.
In lawns, post-emergent herbicides provide easier control of Shepherd's purse than pre-emergents. Spot treat by spraying individual plants, rather than applying a weed and feed over the entire lawn. If you would rather not spray, the herbicide can be brushed on instead. Apply the herbicide in mid-spring and again in mid-autumn if a new crop of shepherd's purse emerges.
These herbicides are most effective when temperatures are between 60-80 degrees F. Do not spray if temperatures are projected to exceed 85 degrees within the next 48 hours. Choose a time when no rain is forecast for at least 24 and preferably 48 hours. To avoid herbicide drift, spray only when the air is still. Drift can harm or kill desirable broadleaf plants such as flowers, vegetables, trees and shrubs.
Post-emergent herbicides should be labeled for use in turfgrass and contain a combination of 2,4-D and MCPP or 2,4-D, MCPP and dicamba. Do not apply any product containing dicamba underneath the canopy of young trees, near shrubs or close to gardens as it can be absorbed by their roots.
Photos: Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010