The client wanted to know how to control the purslane that had taken over her vegetable garden by early September.
DIAGNOSIS / RECOMMENDATION: Mechanical removal is the only option once vegetables have been planted. It was suggested that the client consider using preemergence herbicides well in advance of planting next year.
ADDITIONAL INFORMATION: Purslane (Portulaca oleracea) is one of several broadleaf summer annual weeds that invade lawns, ornamental beds, and vegetable gardens every year. Purslane has a prostrate growth habit, forms low mats, and has thick succulent leaves. [1] Other broadleaf summer annuals that are commonly found include Prostrate Spurge (Euphorbia maculate), which is distinguished by its milky sap, Knotweed (Polygonum aviculare), Common mallow (Malva neglecta), Carpetweed (Mollugo verticillata), and Common Lespedeza or Japanese clover (Lespedeza striata). [1]
All of these summer annuals compete with the cultivated plants for water, nutrients and light. They reproduce by seed and can quickly take over an area. All are managed in a similar way. Wherever possible, these weeds should be removed as soon as possible, before they go to seed. [2] Using a hoe or rotary cultivator may be possible in some gardens, but removal by hand may be the only option in others. If weeds have not yet gone to seed, either compost them or dig them into the soil to add organic matter. Because any herbicide (synthetic or organic) used once weeds are up and large also will damage the vegetable plants, this is not a real option for controlling these weeds. [4]
Planning for weed control starts in the Spring. Consider the use of mulches or weed barriers [2, 3, 4]. Pull weeds when they are small and first appear. An herbicide containing the active ingredient triflualin registered for the proposed crops in the home vegetable garden can be used prior to planting; read and follow all label directions. [4]
And at the end of the season, once the vegetables have been removed, also consider the use of a cover crop or mulch over the winter. Doing so can not only help to improve the soil but also inhibit weed growth, [2, 3, 4] thereby giving you a head start on the following year. Be certain to remove any remaining weeds to reduce the overwintering populations.
from the Bedford Extension MG Help Desk
by Betsy B., Bedford Extension Master Gardener Volunteer; Help Desk Co-Coordinator
September 2018 BAMGA Newsletter Article
RESOURCE LINKS:
[1] https://extension.umd.edu/hgic/purslane
[2] https://pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-364/426-364_pdf.pdf
[3] https://extension.umd.edu/hgic/learn/caring-your-garden
[4] http://pubs.ext.vt.edu/456/456-018/456-018.html pages 2-30 to 2-31.
All resource links live and accessed, August 3, 2018
–A Bedford Area Master Gardeners Association (BAMGA) Publication–
Three ways to find more Help Desk articles!
Click on the More Posts from this Category, perform a Help Desk Category Search or use the Search Bar.