Sour Weed Rumex acetosella

Rumex acetosella, or Sheep sorrel, is a herbaceous perennial herb consisting of a rosette of basal leaves and occasional flowering stalks. The stalks are slender and upright with reddish ridges. The stems branch at the top and the plant reaches a height of 18 inches. It blooms from March to November and produces either red (female) flowers or yellowish-green (male) flowers. The flowers turn into red achene fruits. 

Sheep sorrel prefers full or partial sunlight, mesic to dry conditions, acid and sandy soil but also thrives on loam or clay loam soil at disturbed sites. It is quite aggressive and considered difficult to manage or eradicate because of its creeping rhizome roots. American Cooper or Small Cooper butterfly depend on it for food. There are several uses of sheep sorrel in the preparation of food including a garnish, a tart flavoring agent, a salad green, and a curdling agent for cheese. The leaves have a lemony, tangy or nicely tart flavor. However, they contain significant amounts of oxalic acid, which can be toxic to the kidneys if a sufficiently large quantity of leaves is eaten.

The plant prefers acidic conditions and blueberry farmers are familiar with the weed because it thrives in the same conditions under which blueberries are cultivated.

Diseases, Insects, and Other Plant Problems:

People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take caution if including this plant in their diet. It can aggravate those conditions.