Common Purslane reappears year after year even in fields where it has been well controlled the previous season. There are a couple primary reasons for this, one is fairly easy to minimize and the other is not. The easy one is to stop relying on cultivation to control it. Purslane is a succulent with stems and roots that can survive for several days, reroot and produce seed. Purslane loves newly cultivated open fields where broken stem and root pieces can reroot. The leaves are waxy and have small stomata to help it survive dry conditions for a long time. Some people grow purslane as a microgreen, and they like to plant it by breaking plants into pieces and spreading them on the surface. The seeds also germinate well on uncovered soil surfaces. The more difficult to control reason that Purslane reappears year after year is that it produces a lot of very small seed that can float and blow long distances. It has been reported that one plant can produce tens of thousands of seeds that can survive in the soil for as long as 40 years. Crop seed is developed to all germinate at the same time while weed seed survives because it doesn’t. Some of the seed that germinates in the field was there already and some has moved in in water or wind. The best method to control purslane is to spray it when it is small (inch or less) with a combination of a systemic and a contact herbicide to kill the roots and rapidly desiccate the leaves and stems.

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.