Common purslane (Portulaca oleracea) is a pervasive summer annual weed that frustrates gardeners worldwide. Its exceptional survival mechanisms, including drought tolerance and prodigious seed production, make it resilient in lawns and cultivated beds. This plant quickly dominates an area, competing with desirable plants for water, nutrients, and sunlight. Effectively managing this weed requires a comprehensive strategy combining accurate identification, meticulous physical removal, and targeted chemical application.
Identifying Common Purslane and Its Growth Habits
Common purslane is easily recognized by its distinctive, succulent appearance, allowing it to thrive in warm, dry conditions. The stems are thick, smooth, and often reddish, growing in a prostrate, mat-like pattern from a central taproot. Its leaves are fleshy, oval, and paddle-shaped, typically arranged alternately near the base and oppositely toward the branch tips.
The plant produces small, five-petaled yellow flowers that only open for a few hours on sunny mornings. As a summer annual, it germinates when soil temperatures consistently reach 60°F, usually in late spring or early summer. A single mature plant can produce up to 240,000 tiny, black seeds. These seeds remain viable in the soil for 20 to 40 years, causing long-term reinfestation.
Non-Chemical and Physical Removal Strategies
Meticulous hand-weeding is highly effective for small infestations, but the plant’s unique biology demands specific removal techniques. Due to its succulent nature, common purslane can easily re-root from stem fragments left on moist soil. Consequently, pulling the entire plant, including the taproot, is necessary to prevent regrowth.
If a plant is pulled when mature, its seed capsules may continue to ripen and disperse viable seeds even after the plant is severed from the soil. For this reason, pulled purslane should never be left on the ground to dry or added to a home compost pile. All plant material must be immediately bagged and disposed of in the trash.
Cultural practices focused on prevention are a highly effective long-term strategy for control. A thick layer of organic mulch can suppress germination by blocking the sunlight required for the seeds to sprout. Applying a layer of mulch that is at least 3 to 4 inches deep creates a physical and light-blocking barrier.
Modifying irrigation habits can also discourage this shallow-rooted weed. Deep, infrequent watering encourages desirable plants to develop deeper root systems, making the surface soil less hospitable to purslane seedlings. For large, heavily infested areas, soil solarization can be employed by covering moist soil with clear plastic sheeting for four to six weeks during the hottest part of summer. The resulting high temperatures kill existing plants and sterilize a significant portion of the persistent seed bank.
Herbicide Application for Eradication
Chemical control should be strategically timed to the weed’s life cycle, focusing on both prevention and eradication. Pre-emergent herbicides prevent the germination of new seeds by forming a chemical barrier in the top layer of soil. These products, often containing pendimethalin or dithiopyr, must be applied in early spring before soil temperatures reach the threshold for germination. Pre-emergent products will not affect existing, established plants; they are preventative and must be watered into the soil immediately after application to activate the barrier.
Once the weed is actively growing, post-emergent herbicides are necessary for eradication. Selective broadleaf herbicides, such as 2,4-D, dicamba, or triclopyr, can be used in turfgrass without harming the surrounding lawn. Due to purslane’s thick, waxy cuticle, it can resist herbicide absorption. To overcome this defense, a non-ionic surfactant must often be added to the spray solution to help the chemical penetrate the waxy layer. Non-selective options, like glyphosate, can be used for spot treatment in non-turf areas, but extreme care must be taken to avoid contact with desirable vegetation. Always wear personal protective equipment and strictly follow the mixing and application instructions detailed on the product label.