Pigweed (Portulaca oleracea).

Common Purslane is a member of the Portulaca family and is a Summer annual. Plants emerge from seeds from the late Spring to mid Summer, produce taproots from central growing points, and spread laterally in radial patterns. They do not root at nodes.

Pigweed has branched, red creeping, fleshy hairless stems, that have a water content of over 90%. These stems are 20 to 50 cm long, with succulent leaves and tiny yellow flowers. These 6-8 mm diameter flowers have five notched petals, and only open in full sun.

Category: Purslane is a broadleaf (Dicot) weed.

Flower: Pigweed flowers are yellow, have 4 to 6 petals (often 5), and are 3 to 10 mm long. These are often single or in small clusters, and you can see them in the forks of leaves.

Height: Pigweed is a prostrate weed.

Leaf length: The hairless wedge-shaped leaves of Pigweed, have alternate along stems, and are 5 to 25 mm long,

Leaf width: The leaves of Pigweed are 3 to 15 mm wide.

Pigweed Reproduction.

Pigweed spreads mainly by seeds but it also reproduces vegetatively from stem fragments. Seed germinates at the soil surface in large numbers when the soil temperature exceeds 25°C with an optimal temperature of 30°C.

Pigweed seeds germinate in the late Spring and then through the Summer. They spread long distances by wind, water, and by passing through the guts of birds. The seeds remain viable for up to 40 years.

Three to six weeks after the plants emerge, the plants flower in mid to late Summer, and then can have several flushes of flowers. Common Purslane produces viable seeds as early as three weeks after it emerges, and each plant produces over 200,000 seeds.

Pigweed seeds remain dormant over the Winter months. In the Spring seeds germinate and give rise to new plants in the Summer of the following year.

Seed burial is also a significant factor in Pigweed germination. Seedling emergence is greatest at the soil surface, and then declines with increasing soil depth.

Pigweed is susceptible to low temperatures, and begins to die once the temperatures begin to drop in the early Autumn.

Comments: Pigweed is thick, and flat at the nodes. Its taproot is white or brown in colour with fibrous hairs that reach to a depth of 30 to 50 cm. The stems of are maroon to purple, hairy, and erect, and remain moist and viable for several days after cultivation.

Habitat: Pigweed is a common weed of crops, pastures, gardens, disturbed sites, waste areas, footpaths and roadsides. It favours high fertility soils with moderate moisture, but grows in nearly all soil types.

For more information on weeds check this weed ID Chart.

The distribution map of Pigweed in Australia is courtesy of The Living Atlas of Australia.

You can control Purslane or Pigweed by cultural and chemical means, but successful management of this weed is best if you adopt an integrated approach.

• The first step to manage Pigweed (Portulaca oleracea) is to prevent it in the first place. This is because once Common Purslane establishes it is difficult to control.
• Don’t bring Common Purslane into un-infested areas and clean equipment like mowers etc.
• In healthy, established turf grass, Pigweed is usually not a problem. It is more of a problem in weak, poorly maintained turf grass.
• Feed your turf properly and cut it at the right height to maintain a healthy, competitive turf cover.
• If Purslane is flowering remove the plants offsite to make sure that it does not release viable seed.

We have seen big issues with Pigweed after cultivation, as this tends to bring deeper weed seeds to the surface where they then germinate after irrigation.

In Australia, a number of chemicals are registered for Pigweed (Portulaca oleracea), for instance: 2,4-D, Dicamba, Pendimethalin, Propyzamide, and Glyphosate but not all of these for turf use.

Pre-emergent Control of Pigweed.

If you use pre-emergent herbicides to control Purslane make sure they are present at the soil surface when seedlings emerge and are activated with an irrigation. If you treat mature Pigweed too late in the season, control is often erratic as seed set may have already occurred.

The University of California notes that preemergent herbicides, like Dithiopyr, Pendimethalin, and Propyzamide are particularly good at stopping Pigweed seeds in their tracks. However these do not have a registration for this weed in Asutralia in turf grass.

• Metolachlor is suppreses Pigweed.
• BASF Freehand herbicide.

Post emergent Control of Pigweed.

Dicamba, and 2,4-D are effective post emergent herbicides, and are available to the home gardener. Another option for Pigweed control is Quali-Pro Crest, but If you use this, use it with a Crop Oil Concentrate like ProForce Voltage MSO.

In South Africa, Casper Turf is registered to control Purslane or Pigweed at 600 – 800g /Ha.

Table of Selective Post emergent herbicides for Pigweed or Purslane.

Non Selective Control of Pigweed.

• Glufosinate-ammonium.
• Glyphosate. You can use Glyphosate as a non selective option to control Pigweed or Purslane. If you use Glyphosate, and water quality is an issue then use ProForce Manta Ray.

The following are non-selective but also have a long term residual and stop any re-growth of Pigweed (Portulaca oleracea).

• Renegade. Renegade stops the germination of Purslane for up to 12 months, and reduces the need for multiple herbicide applications.
• Numchuk Quad. This gives effective post and pre emergent Purslane control for up to 12 months.
• Cortex Duo. Cortex Duo gives a rapid knockdown of Pigweed, and residual control for up to 3 months, and is safe to use around trees.