Carissa macrocarpa aka Natal Plum

Carissa macrocarpa, or Natal plum, is an evergreen shrub. It belongs to the dogbane family, Apocynaceae. Its native range runs from Kenya to South Africa. It grows in coastal scrub and on sand dunes. Gardeners grow it across warm parts of the world. It has spread beyond gardens in Florida, Texas, and Asia.

The shrub forms a dense, rounded mass of branches. Several stems can rise together from the base. Sources differ on its size in gardens. Some give 5–7 feet [1.5–2.1 m] as the usual height. Others describe plants 15–20 feet [4.6–6.1 m] tall and wide. Exceptional plants may reach 30 feet [9.1 m] tall. Growth proceeds at a moderate rate. Stout, forked spines make the branches hard to handle. Young stems are green, with ridges along their length. Older twigs turn greenish brown and may stay glossy. The thick, oval leaves grow in opposite pairs. Their dark green surface shines, and their tips are sharp. The leaves stay on the plant through winter.

White flowers have five petals and a star shape. Their scent recalls jasmine. In warm climates, blooms can appear in every month. The fleshy, oval fruits start green and ripen red or purple. Their thin skins enclose many seeds. Ripe fruit is edible, fresh or cooked. Its sweet to tart taste recalls raspberries and cranberries. Some fruit has an astringent taste. Cooks use it for jelly, syrup, pickles, and tarts. Despite its name and shape, it is not a plum.

Grow Natal plum in full sun or light shade. It accepts sand, loam, and clay if water drains well. It also tolerates both acid and alkaline soils. Established plants withstand drought and need no extra watering. Salt spray makes it suited to coastal gardens. Hardiness reports range from USDA zones 8–11 to 9–10. Cold can kill young growth before older wood. Containers allow gardeners to move plants indoors for winter.

Dense growth and spines suit hedges, screens, and foundation beds. The plant also works as a border specimen. It draws birds and butterflies and resists deer. Shearing can keep its size in check. Florida red scale, leaf bacteria, and root rot may occur. Poor drainage raises the risk of root rot. The sap contains latex and has low toxicity to humans. Swallowing much sap may cause vomiting or diarrhea. NC State lists it as non-toxic to dogs, cats, and horses.