Virtual Weed Walk: Purslane
by Karyn Maier
Purslane (Portulaca oleracea) is an annual creeping groundcover thought to be original to the Middle East, North Africa and the Indian subcontinent, but is now naturalized throughout the world. In addition to its successful migration, the tiny but hardy herb has been cultivated for food and medicine for more than 4,000 years, although many gardeners resent its habit of persistently cropping up in unwanted places, such as in cracks in paved driveways or cement sidewalks, or between stone pavers.
However, like many plants labeled as pesky weeds, purslane is highly nutritious. In fact, it makes a tasty addition to salad and sandwich greens. It is rich in antioxidants and anti-inflammatory compounds (apigenin, glutathione and kaempferol), calcium, iron, magnesium and potassium, as well as vitamins A and C. Purslane is also unique in that it is one of the very few plants that contain omega-3 essential fatty acids.
The stems, leaves and flowers are edible, all of which impart a salty yet slightly tart or sour taste. The intensity of this flavor profile is heightened in plants grown in very hot, dry climates. That's because the herb adapts to these conditions to save moisture and energy by utilizing the Crassulacean acid metabolism (CAM photosynthesis), which allows the plant to produce fuel for energy during the day but only exchange gases at night. The trapped carbon dioxide in the leaves is converted to malic acid and then subsequently to glucose to be stored during the day. So, if you like your purslane on the tart and sour side, be sure to harvest the herb early in the day when the malic acid concentration in the leaves is at its highest.
Purslane can also be pickled, juice with other greens, added chopped to dips and sauces, or sauteed or steamed as a vegetable, or dropped into soup like spinach. A high mucilage content makes the herb a good thickening agent in soups and stews. While the plant isn't in high demand as a food or supplement in North America (although it is offered at some farmer's markets), it is often used as a foraging crop or supplement fodder for grazing animals. Take note if you raise chickens: hens that feed on purslane will lay eggs with a high omega-3 fatty acid content.
Known in China as ma chi xian and as the “vegetable for long life," purslane has been used in traditional Chinese medicine for centuries to clear heat, cool the blood and to staunch bleeding. In Ayurveda, the traditional system of healing in India, purslane is used to counter cough and excess mucous associated with asthma and other respiratory conditions. The herb also has a history in Ayurvedic medicine for treating indigestion and ulcers, as well as disorders of the eyes.