Natal plum — an underappreciated fruit that makes a great jam

Natal plum (Carissa macrocarpa) grows all over Southern California, especially in San Diego. It is generally planted as an ornamental hedge.

Given the dense growth and formidable thorns, it creates an excellent barrier against would-be invaders. The plant is native to the east coast of southern Africa and holds up well against salt-laden winds, hence its success along our coast.

It produces shiny green leaves and white flowers with a perfumed scent. It is evergreen and blooms for months at a time. The flowers turn into plump, crimson plums, especially in the warm summer months, but can be found all year.

The fruit is referred to as a Natal plum after the Natal province in South Africa, where it is indigenous to the coastal areas. In South Africa the fruit is also called num-num.

What is not widely appreciated is that these plums are very edible when slightly soft. The sweet, tart flavor is unique and delicious. The fruit can be eaten by hand or made into jams, jellies and pies.

The fruit is rich in vitamins (C, thiamine, riboflavin and niacin) as well as minerals (calcium, iron, magnesium, phosphorous, potassium and sodium).

Some claim the leaves and stems of the plant are poisonous, especially to animals. However, this is a myth — the latex in Carissa is non-toxic [according to the South African National Biodiversity Institute’s plant information website, plantzafrica.com]. In any event, avoid eating the leaves!

Recipe

Natal plum (num-num) jam

• 2 to 3 pounds Natal plums (ripe, slightly soft to the touch; beware of thorns while picking)

• ½ cup water

• 2 cups apple juice

• 2 tablespoons fresh lemon juice

• 1¾-ounce package of pectin

• 4 cups sugar

Instructions:

• In a pot, mash the plums and add the water. Bring to a boil for 10 minutes, stirring occasionally. Mash again and boil for a further two minutes.

• Add the apple juice, lemon juice and pectin. Bring to a boil for 10 minutes.

• Add the sugar, stir and boil for one minute. Boil longer for a more concentrated, thicker jam.

• Pour into clean pint jars, leaving ¼-inch head space.

• Place the sealed jars in a pot filled with water and bring to a boil for 10 minutes to destroy any bacteria and harmful enzymes.

Dr. Peter Sacks is a resident of La Jolla. He says his family has used this recipe for many years. ◆