The name Coleus is derived from the Greek koleos, meaning ‘a sheath’, and refers to the fused stamens of the type species for the genus.The species name hadiensis is derived from the Arab name from where it was first collected, the Hadiyah Mountains in Yemen. This species was until 2019 placed in the genus Plectranthus, until molecular studies on Plectranthus and closely related genera by Paton et al resulted in the revision of the genus in 2019 and the re-instatement of the genus Coleus. This species falls within the ‘coleus clade’ and is therefore renamed as Coleus hadienis. The name Plectranthus is derived from the Greek words anthus meaning ‘flowers’ and plectron meaning ‘spur’, which refers to the characteristic spur on the base of the corolla tube of the type species for the genus, hence the common name spurflower. 

Coleus is a genus in the sage family, Lamiaceae. Members of the Lamiaceae typically have square stems, whorled flower arrangements, aromatic oils and two-lipped flowers.

Coleus hadiensis was first discovered by Pehr Forsskål in Hadiyah, Yemen and it was named Ocimum hadiensis in 1775 in the Flora of Egypt and Arabia (Van Jaarsveld 2006). The genus Plectranthus was not yet established, but it was the first Plectranthus to be described although it was only transferred to Plectranthus in 1894 by the botanists Schweinfurth and Sprenger. Paton transferred it to Coleus in 2019.

Coleus hadiensis is closely related to Coleus grandidentatus which has light green leaves with large-toothed margins, and Coleus madagascariensis which has smaller leaves, a cascading growth habit and white flowers.

Three varieties of Coleus hadiensis are recognized:
var. hadiensis which occurs in the middle and coastal areas of KwaZulu-Natal and the eastern parts of South Africa;
var. tomentosus, which is found in semi-coastal areas from the Kei River towards the coast of KwaZulu-Natal and extending inland along the Mpumalanga Drakensberg and is a large, erect shrub with subrotund leaves and occasionally with tuberous roots;
var. woodii, which has tuberous roots that help it to survive fire in the dry woodlands of the Eastern Cape, KwaZulu-Natal and Mpumalanga.