Carissa is a genus of evergreen, often spiny shrubs and scrambling vines in the dogbane family (Apocynaceae), comprising around 20 species native to tropical and subtropical regions of Africa, Asia and Australasia. Renowned for their glossy, opposite leaves and fragrant, star‑shaped white flowers, Carissa species also produce smooth, cherry‑like berries—some varieties yielding sweet, edible fruit prized in jams and preserves. Beyond their ornamental appeal in hedges and container plantings, many Carissa have traditional uses: their latex and bark feature in folk medicine, while their dense growth habit makes them ideal for wildlife‑friendly shelter and barriers in water‑wise gardens. With their blend of beauty, resilience and practical value, Carissa shrubs bring both ecological and cultural richness to landscapes around the world.

Carissa tetramera, commonly known as Sand Num-num, is a South African indigenous evergreen fruit bearing shrub found in the KwaZulu-Natal, Limpopo and Mpumalanga provinces, extending into Kenya, Tanzania, Zimbabwe, Mozambique and Eswatini, growing in dry open woodland. The specific epithet tetramera means ‘four parts’, referring to the flower. The plant is armed with strong spines that are usually forked. When grown as a hedge it becomes an impenetrable barrier. Carissa tetramera grows as a shrub up to 3 metres (10 ft) tall. Its strong-scented flowers feature a white corolla, often tinged pink. The edible fruit is red to purple-black when ripe.