Common name: Marula

Marula is a fruit-bearing tree originating in low rainfall, open woodland areas in Sub-Saharan Africa, its natural range extending from Ethiopia, in the east of the African continent to South Africa.

It is a medium-sized, deciduous tree up to 18 m (60 ft) tall, though is more typically under 12 m (40 ft) with a single, short trunk and wide-branching crown. Under favourable conditions, it can grow by up to 1.5 m (5 ft) a year. The bark is grey and smooth on young trees but peels off in large, flat flakes, leaving behind a mottled surface. As the tree ages, it becomes cracked and rough.

The leaves are feathery, made up of dark or pale green oval leaflets arranged in pairs along the length. They fall off the tree in the dry season to conserve water, leaving the branches bare until the rainy season, when the new leaves emerge.

The flowers are small, red, purple or pink when young, becoming pale pink to creamy-white as they open and are either female or male on separate trees, borne on long flower-spikes arising at the tips of the branches. They come into bloom at the end of the dry season when the tree is leafless and the new leaves are just starting to emerge.

Only female trees bear fruit, which are round and plum-sized, about 3 to 4 cm (1 to 1.5 in) in diameter and pale green, with variation in the size, shape and quality among the different varieties. When mature, they fall to the ground in great numbers, after which the skin changes colour to pale yellow and the pulp softens. The pulp clings tightly to the stone, which is hard and encloses one to three edible kernels. 

It is a heavy-bearing tree, with individual trees reportedly producing between two and ten thousand fruit in a season.

Use

The fruit are collected after they have fallen to the ground and are then stored until they ripen, usually within a few days, but must be eaten or processed within days after that as they quickly ferment and start to deteriorate.

The pulp of good quality ripe fruit is aromatic, juicy and white with a jelly-like consistency and sourish taste, described by some as having a likeness to mango and guava. However, the texture and flavour are highly variable, with some fruit having a dry texture and turpentine aftertaste, which may be due, in part, to varietal differences or growing conditions, but this is not yet fully understood. The pulp is made into juice and other beverages, jam, fruit preserves and branded cream liquors such s 'Amarula Cream', which is distributed and marketed worldwide.

The fruit are also an important part of the diet of native wildlife, including elephants and different ape species, some of which relish the fermented fruit and become intoxicated after eating them. They are also eagerly foraged on by cattle and other livestock.

The seed kernels can be eaten as a nut and their taste is said to remind of walnuts, hazelnuts or macadamia nuts, but the shell is difficult to crack open. They have a protein content of around 28% and an oil content of around 50%. The oil is edible and compares favourably with olive oil. It is expressed from the nut for use in cooking but is more widely used as an ingredient in cosmetics, such as lipstick and skincare (moisturising) products, on account of its natural oxidation stability, which gives it a long shelf-life. One metric ton of fruit can be converted into around 60 litres of oil, the equivalent of 7 gallons of oil for every thousand pounds of fruit.

The flowers are a major source of nectar for honeybees, particularly in Mozambique and, to a lesser extent, South Africa, with the honey described as almost white to light amber and with a rich, agreeable flavour.

A gum exuded from the bark is collected and dried in its native range, then is mixed with soot and water to make ink.

The tree provides people and livestock with welcome shade from the searing sun.

Health use

The fruit pulp is rich in Vitamin C as well as having good quantities of magnesium and phosphorus.

Climate

Grows and fruits well in dry to moderately humid subtropical and tropical lowland to mid-elevation climates, generally frost-free areas with annual lows of 13 to 25°C, annual highs of 26 to 37°C, annual rainfall of 400 to 1600 mm and a dry season of 5 to 7 months.

Growing

New plants can be started from seed or cuttings, with cuttings from known female and male trees consider good practice, so as to establish a good male to female ratio for pollination and fruit production.

It performs best on free-draining loam and sand soils of a moderately acid to neutral nature, generally with a pH of 5.5 to 7.0 and on sites with full sun exposure. It has shown good tolerance to saline water but poor tolerance to shade and slow-draining or waterlogged soils.

Problem features

Marula trees produce lots of fruit, some of which end up in the stomachs of large animals that move around, or they are taken by small animals some distance from the parent tree and the seed discard. It is listed as a weed in at least one reference publication, but there does not appear to be any record of it anywhere as a serious weed.

The roots send up suckers which enable trees to colonise the ground around them, creating dense thickets over time.

Books

• Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London

• Crane, E., Walker, P. & Day, R. 1984, Directory of important world honey sources, International Bee Research Association, London

• Food and Agriculture Organization of the United Nations (FAO) 1986. Some medicinal forest plants of Africa and Latin America, Forest Resources Development Branch, Rome, Italy

• Food and Agriculture Organization of the United Nations (FAO) 1988, Traditional food plants : a resource book for promoting the exploitation and consumption of food plants in arid, semi-arid and sub-humid lands of eastern Africa, Food and Nutrition Paper No. 42, Rome

• Howes, F. N. 1949, Vegetable gums and resins, Chronica Botanica Company, Waltham, Massachusetts

• Lopez, C., Shanley, P., eds. 2004. Riches of the forest: for health, life and spirit in Africa. Bogor, Indonesia, Center for International Forestry Research (CIFOR)

• Martin, F. M., et al. 1987, Perennial edible fruits of the tropics : an inventory, U.S. Dept. of Agriculture (USDA), Agricultural Research Service, U.S. Government Printing Office (GPO), Washington, D.C.

• Mollison, B. 1993, The permaculture book of ferment and human nutrition, Tagari Publications, Tyalgum, New South Wales

• National Research Council (Board on Science and Technology for International Development) 2008, Lost Crops of Africa: Volume III: Fruits, The National Academies Press, Washington D. C.

• Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

• Stewart, A. 2013, The drunken botanist : the plants that create the world's great drinks, 1st ed., Algonquin Books, Chapel Hill, North Carolina

• Van Wyk, B. E. 2005, Food plants of the world: an illustrated guide, 1st ed., Timber Press, Portland, Oregon

• Wickens, G. E 1995, Edible nuts, Food and Agriculture Organization of the United Nations (FAO), Rome

• Winter, R. 2009, A consumer's dictionary of cosmetic ingredients : complete information about the harmful and desirable ingredients found in cosmetics and cosmeceuticals, 7th ed, Three Rivers Press, New York