Carissa wyliei is an erect shrub or small tree with slender branches often using sturdier surrounding plants for support. Tiny spines may be seen on its pale green bark. Carissa species in South Africa usually have hefty spines.

Clusters of long tubed flowers appear in spring and summer. The white corollas are sometimes tinged pink. The large fragrant flowers have pointed petals up to 12 mm long. Flowering happens from late winter through summer.

The oval fruit is fleshy and red when ripe, about 10 mm long and 5 mm wide. Fruits are usually seen on the plant from mid-spring to autumn.

C wyliei may have been discontinued as a separate species, sunken into C. bispinosa, a variable species.

Another photo of C wyliei appears in the Forests Album (Coates Palgrave, 2002; Pooley 1993).