Sheep Sorrel (Acetosella vulgaris)
© Harry Rose
Introduced, cool-season, perennial, slender, erect herb to 40 cm tall. Rhizomes can form dense mats in some areas. Leaves form a rosette at the base of the plant; they are 2-7 cm long and shaped like an arrowhead, with 2 projecting lobes at their base. Flowerheads are narrow panicles with small rusty red flowers. Flowering is in spring. Possibly a native of Europe, it is a weed of pastures, waste ground and along roadsides; most common on acid, low fertility, sandy soils. Often considered to be a weed of acid soils, but really indicates poorly competitive pastures, which may be caused by soil acidity. Is grazed, especially by sheep, but contains an oxalate that occasionally poisons stock where sorrel is abundant. Grazing systems (rotational grazing and spelling) that promote good groundcover and competition will reduce sorrel. Fertiliser, and sometimes lime, is important to maintain competitive pastures. Herbicides used to control sorrel also kill legumes.
Photo taken on 29 Jul 2011