WordNet sense 1 (very large closely branched South African shrub having forked bright green spines and shiny leaves):

amatungulu, Carissa grandiflora, Carissa macrocarpa

WordNet sense 2 (South African shrub having forked spines and plumlike fruit; frequently used as hedging):

hedge thorn, Carissa bispinosa

WordNet sense 3 (edible scarlet plumlike fruit of a South African plant):

carissa plum