Sheep's sorrel (Red sorrel, Sour weed, Field sorrel)
Rumex acetosella is a species of sorrel, bearing the common names sheep's sorrel, red sorrel, sour weed, and field sorrel. The plant and its subspecies are common perennial weeds. It has green arrowhead-shaped leaves and red-tinted deeply ridged stems, and it sprouts from an aggressive and spreading rhizome. The flowers emerge from a tall, upright stem. Female flowers are maroon in color.
A perennial herb that has a slender and reddish upright stem that is branched at the top, reaching a height of 18 inches (0.5 meters). The arrow-shaped leaves are small, slightly longer than 1 inch (3 cm), and smooth with a pair of horizontal lobes at the base. It blooms during March to November, when yellowish-green (male) or reddish (female) flowers develop on separate plants at the apex of the stem, which develop into the red fruits (achenes).
Rumex acetosella is widely considered to be a hard-to-control noxious weed due to its spreading rhizome. Blueberry farmers are familiar with the weed because it thrives in the same conditions under which blueberries are cultivated.