Sheep Sorrel a Perennial Weed
Sheep sorrel (Rumex acetosella), also called field sorrel, red sorrel, and sour weed, is an herbaceous perennial member of the buckwheat family (Polygonaceae). It is widely regarded as an aggressive, troublesome weed, difficult to manage and eradicate. Native to Eurasia and the British Isles, sheep sorrel is naturalized throughout most of North America. Hardy in USDA Plant Hardiness Zones 4 through 8 will grow in full sun to part shade. It thrives in sandy, acidic soil, preferring a pH lower than 6.
Oblong,1 to 3-inch-long, arrow-shaped leaves form a rosette of foliage near the ground, spreading 4 to 6 inches. Slender, upright, reddish flower stems reach a height of 18 inches and terminate in clusters of short, spike-like stems bearing tiny flowers. Blooming from March through October, it typically produces male and female flowers on separate plants. Female flowers are red, and male flowers are yellowish-green. The flowers produce a single red to burgundy, triangular-shaped seed.
While many people consider sheep sorrel a weed, others consider it an herb. It has been used medicinally and eaten for centuries. Present-day foragers still seek out its tart, lemony-flavored leaves and use them in cooked dishes or as salad greens. Humans are not the only ones who use its leaves as a food source. It is the host plant for American copper butterfly larvae.
Sheep sorrel is wind-pollinated, and its seeds are dispersed by wind, water, and insects. One plant can produce up to 1,600 seeds per year, which may remain dormant for as many as 80 years. While it is a prolific seed producer, its primary means of reproduction is vegetative through its roots and rhizomes. A shallow, horizontal spreading system of roots and rhizomes allows the plant to multiply quickly. Rhizomes are a type of underground plant stem that is capable of producing shoots and the root systems of new plants. As the rhizomes grow horizontally in the top 8 inches of the soil, new shoots sprout, creating more plants. It colonizes rapidly and may persist for 15 to 20 years.
It can be difficult to eradicate using only cultural or non-chemical methods. Its persistent seeds and ability to regrow from small sections of root left in the ground make control and eradication difficult. Hand-pulling the plants is often ineffective because removing the entire root mass and all of the rhizomes is difficult. Managing your soil pH may be helpful. Raising your pH to 6.5 to 7 in areas where you are not trying to grow acid-loving plants, such as blueberries, is recommended. Smaller populations may be controlled by repeated cultivation. The continual disruption and removal of the foliage may eventually starve the roots. Cultivation should be frequent, but plants should be allowed to produce two or three inches of new growth between cultivations to provide maximum depletion of root reserves. This method is labor-intensive and may be impractical for larger populations. In that case, the cautious use of herbicides may be necessary. As with using all chemicals, it is very important to follow the manufacturer's instructions on the label carefully. For additional questions or assistance, contact your county's Extension office.
