The genus Greyia has been placed ing the Greyiaceae family. The other two species in the Greyiaceae family, Greyia radlkoferi and G. sutherlandii are dormant and leafless in winter, unlike G. flanaganii, which is evergreen. G. radlkoferi is found in Mpumalanga and Limpopo (Northern Province) and G. sutherlandii is from KwaZulu-Natal. The greyias of South Africa do not appear to have close relatives among the extant flora of the world. Greyiaceae belongs in the monotypic order Greyiales that was formerly described and placed between the Saxifragales and Francoyales.

Greyia sutherlandii is relatively hardy, and fairly drought resistant. Under suitable conditions with well-drained soil and good aeration, it is a fast grower but may not grow taller than 3 m in a garden. It does not flower well in coastal areas. This tree is best for smaller gardens and courtyard gardens. It can also be grown in a pot on the veranda. Some farmers use it for fencing. Greyia sutherlandii is a small tree, 3 to 7 m high. It is deciduous and in late autumn the leaves turn shades of bright red. This is a most decorative plant and is becoming popular as an ornamental subject in gardens.