Common purslane(Portulaca oleracea)
Compiled by Mary Rumph, Montana State University, Powder River County Extension, and
Marjolein Schat, Montana State University from the following sources:
Identification and Life Cycle
Common purslane (Portulaca oleracea) is an annual in the purslane family (Portulaceae). Synonyms include P. neglecta and P. retusa. Common purslane is a prostrate, succulent annual that often forms a dense mat. The reddish stems originate from a central rooting point, radiating out like spokes of a wheel. The stems vary in length, commonly grow up to 12 inches. Leaves are stalkless (sessile), oval, smooth, succulent, and shiny, and vary from 1/2 to 2 inches in length. The leaves, although generally arranged opposite, may also occur alternately along the stem, particularly near the base. Small (3/8 inch), five-petaled, yellow flowers are borne singly in leaf axils and open only in sunshine. Seeds are borne in a small pod. Seeds are reddish brown to black, oval, and tiny (about 1/64 to 1/32 inch in diameter).
Common purslane is widely distributed throughout the United States. Common purslane can grow in a variety of soil types, and is highly tolerant of drought conditions.
Some livestock can tolerate common purslane in small amounts, but large amounts can be toxic. Common purslane serves as an alternate host for various plant diseases and nematodes. Its ability to produce plenty of seeds can result in the easy colonization. It forms a dense mat that prevents seedlings from germinating, and competes for soil moisture and nutrients. It can reduce yield from 20-40%, depending on the crops.
Biology and Ecology
Common purslane germinates in late spring when soil temperatures reach about 60°F. It germinates very near to or at the soil surface in large numbers after an irrigation or rain. Most of the tiny seedlings die, but the survivors grow rapidly and can produce flowers in a few weeks. The fleshy stems of common purslane can remain moist and viable for several days after cultivation and hoeing, and reroot to form “new” plants when gardens or fields are irrigated. Common purslane is a prolific seeder. A single plant may produce 240,000 seeds, which may germinate even after 5 to 40 years.
Management should target preventing new infestations or treating the seedling stage since common purslane can be difficult to eradicate once it becomes established.
Purslane sawfly is an insect that feeds and reproduces on common purslane. Unfortunately, by the time it develops sufficient numbers to have an impact on the common purslane population, seed development and much of the damage from purslane competition has already occurred.
Mechanical and Cultural Control
In irrigated areas, cultivation after irrigation is effective on reducing weed populations, though this method can expose buried seeds as well. When this is used as treatment on larger plants, care must be taken to remove all plant parts to avoid the possibility of re-rooting.
Common purslane resistance to photosystem II inhibitors and ureas and amides was reported in Michigan in 1991. For more information on herbicide resistance in common purslane, please see http://www.weedscience.org/Summary/USpeciesCountry.asp?lstWeedID=138&FmCommonName=Go .
For herbicide recommendations for specific grain rotations and weeds in Montana, please see the MSU Herbicide Chooser Tool.
Examples of herbicides that can be used to manage common purslane
Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.
|Herbicide Active Ingredient trade name||Mode of Action||Product per Acre||Application Time or Growth Stage|
|Pendimethalin||Microtubule assembly inhibition|
|*Prowl||4 pints||In established Alfalfa for Forage/Hay apply prior to weed emergence. Applications can be made in the fall after the last mowing/cutting, during winter dormancy, in the spring, or between cuttings. Applications should be made prior to the alfalfa reaching 6 inches in regrowth.|
|Imazamox||Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)|
|*Raptor||4 ounces||Apply postemergence prior to bloom stage but dry peas have at least 3 pairs of leaves and common purslane is less than 3 inches tall|
|Grass Grown for Seed|
|Dicamba||Action like indole acetic acid (synthetic auxins)|
|*Clarity||8 - 32 ounces||Apply 8-16 ounces to seedling grass after the crop reaches the 3 - 5 leaf stage. Apply up to 32 fluid ounces on well-established perennial grass. For best performance, apply when weeds are in the 2 - 4 leaf stage|
|Wheat and Barley|
|Metasulfuron; thifensulfuron; tribenuron||Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)|
|*Ally Extra||0.2 - 0.4 ounces||Apply in the spring or fall Make applications after the crop is in the 2-leaf stage, but before the flag leaf is visible and when the majority of weeds have emerged and are actively growing.|
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.
For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=common%20purslane&Start=1&results=33