Pachycarpus concolor subsp. transvaalensis is an erect perennial that usually grows unbranched stems to heights of around 70 cm from a tuberous rootstock. The plant contains a milky latex, quickly seen when the skin is broken. This feature is common in its family, the Apocynaceae.
The subspecies is found from the north of KwaZulu-Natal to the Mpumalanga Highveld, as well as in Eswatini.
The habitat is grassland slopes and rocky outcrops at higher altitudes. The habitat population of the subspecies is deemed of least concern early in the twenty first century (Pooley, 1998; iNaturalist; iSpot; JSTOR; http://redlist.sanbi.org).