Mentha longifolia, commonly known as wild spearmint or horse mint and balderjan in Afrikaans, is a rhizomatous herb reaching 1,5 m in height. Mature leaves show the characteristic sunken veins on their upper surfaces. The lanceolate, stalkless leaves curve down to their tapering tips as they lengthen to their full size.

The dense cluster of acutely pointed emerging leaves ascending at the stem tip are pale to yellow green. Leaves of this plant may be toothed or entire and sometimes hairy, smelling of mint when crushed.

The species distribution covers most of South Africa. The habitat is moist places and river banks. Three subspecies of M. longifolia exist in South Africa, as well as some not found here. The local three are considered to be of least concern in terms of survival in their respective habitats early in the twenty first century.

All three are associated with use in cold drinks, teas and various medicinal applications prepared from the leaves (Manning, 2009; Roberts, 1990; http://redlist.sanbi.org).