Purslane (Portulaca oleracea)
Purslane is a low-growing, fleshy annual weed that spreads rapidly across bare or open areas of lawns, paths, and gardens during the warmer months. It thrives in dry, compacted, or disturbed soil and is most active through late spring and summer, dying off with the first frosts of autumn.
This weed is especially common in sunny, well-drained sites, where it forms thick mats that crowd out lawn grass and young seedlings. Purslane’s ability to survive drought and regenerate from stem fragments makes it one of the more persistent summer weeds in New Zealand lawns and gardens.
Identification
Purslane grows as a flat, sprawling mat with smooth, reddish stems and fleshy, spoon-shaped green leaves. The stems radiate from a central taproot but do not root at every node. Leaves are arranged opposite or in clusters along the stems, with a waxy, succulent texture.
Small yellow flowers form in the leaf joints during summer, each producing tiny seed capsules that burst open when mature. A single plant can produce tens of thousands of fine, black seeds that remain viable in the soil for years.
When crushed, the plant releases a mild, slightly sour scent, and its stems retain moisture long after being uprooted — which allows it to regrow if left on damp soil.
Why It’s a Problem
Purslane spreads quickly over bare patches in lawns, forming dense mats that smother desirable grass. Its thick, moisture-retaining leaves allow it to survive where other weeds struggle, and its sprawling growth makes mowing ineffective.
In lawns, it can quickly take over areas of weak turf, while in garden beds it competes for space and nutrients with seedlings and ornamentals. Because it produces huge quantities of seed, even a small infestation can return the following summer if left untreated.
Management and Prevention
Cultural control methods:
- Maintain dense turf: Keep lawns healthy and well-fertilised to shade the soil and prevent purslane seed germination.
- Avoid overwatering: Moist but compacted soil encourages growth. Improve drainage and aerate compacted areas.
- Hand removal: Pull or hoe young plants before flowering. Remove all plant fragments, as even small pieces can re-root.
- Mulching garden beds: A thick mulch layer blocks light and prevents new seedlings from emerging.
- Minimise soil disturbance: Turning over the soil can bring dormant seeds to the surface where they germinate.
Chemical Control:
Purslane is generally easy to control with selective herbicides when treated early. Apply when plants are young and actively growing.
Effective herbicide options include:
- Dicamba/MCPA/2,4-D mixtures (Cleansweep, Soft Touch) for lawns and turf areas.
- Triclopyr/picloram mixtures (NZLA Gold) for more established infestations.
- Glyphosate for spot-spraying in gardens, paths, and driveways. Avoid contact with desirable plants as it is non-selective.