Common purslane

Common purslane is a succulent, mat-forming summer annual with smooth, fleshy, reddish stems that radiate from a central taproot and lie flat against the soil. The thick, paddle-shaped leaves are smooth and glossy, green above and often maroon-tinted beneath, roughly half an inch long, and are clustered or nearly opposite along the stems and at the stem tips. Small yellow flowers with five petals open in the leaf clusters during warm, sunny weather and give rise to tiny capsules packed with abundant minute black seeds. The fleshy, water-storing stems and leaves are the most distinctive identifying trait and separate purslane from spurges, which exude milky sap.

Common purslane forms dense, succulent mats that smother and crowd out turfgrass, creating thick, fleshy patches that contrast sharply with the surrounding stand and leave thin or bare areas when the mats are removed or die at frost. Its vigorous warm-season growth lets it overtake gaps in stressed summer turf and in new seedings, and because each plant sheds vast numbers of long-lived seeds, infestations tend to intensify and recur in following years.

Common purslane is a warm-season summer annual that reproduces by seed and is most visible during the hottest months. Seedlings emerge as soils warm, plants develop rapidly, and small yellow flowers appear roughly four to six weeks after emergence, maturing by late summer to release enormous quantities of tiny black seeds into the soil. The plant's succulence allows uprooted or cut pieces to survive and even re-root under moist conditions, and seeds remain viable in the soil for many years, so a single season of seed set fuels long-term infestation.

Purslane grows best in full sun and tolerates poor soils and moderate drought, making it a frequent invader of poorly maintained, thinning turf and of newly established lawns seeded in late spring or summer. It exploits open, sunny ground where the canopy is incomplete, hugging the soil at only three to four inches tall and spreading into mats that can reach several feet across. Hot, dry summer conditions that stress cool-season turf, combined with bare or thin areas, strongly favor its establishment and rapid spread.