Dwarf Ambarella tree.
Dwarf Ambarella seedling, one-year-old.
Photo by Ray Johnson, Queensland

Ambarella, also called Otaheite apple, Polynesian plum, hog plum

Spondias cythera (dulcis)

Origin:

Native to the Indo-Malaysian region and now spread throughout the tropics.

Climate:

It grows well in warm sub-tropical climates and in the tropics up to 700m. There is some drought tolerance and foliage may be shed briefly when under stress. There is very little frost tolerance.

Plant Description:

A rapidly growing tree with a rounded canopy, 10-15m high in its preferred environment but less elsewhere. In cooler sub-tropical climates it can be semi-deciduous. The pinnate leaves, 20-60cm long, have 9-25 pairs of glossy elliptic leaflets, 6-10cm long, with a short petiole.

Relatives:

Ambarella is a member of the Anacardiaceae Family, as are mangos, red and yellow mombins, cashew, pistachio, marula and imbu.

Soils:

Undemanding if well-drained.

Propagation:

Trees are often grown from seeds which germinate within a few weeks; seedlings may also be used as rootstocks for grafting and budding. Some seeds are polyembryonic. While cuttings and air layers are possible, seedlings and grafted trees are more vigorous than the other propagation forms. Large variations in fruit quality are found across trees, with the most important features being the levels of sweetness, acid and fibre.

Cultivars:

There are no recognised cultivars resulting from controlled breeding trials but random trees with favoured qualities have been selected. There is a dwarf type, 1-5-3m high, that is much more precocious than normal plants.

Flowering and Pollination:

Inflorescences occur in terminal panicles with individual small white flowers appearing before the leaves. Each panicle consists of male, female and hermaphrodite flowers (ie they are polygamo-monoecious). Calyx lobes are triangular and the petals ovate-oblong. Flowering occurs in spring in the sub-tropics. Pollinators are bees and other insects.

Cultivation:

Young trees should be shaded for the first 1-2 years, but thereafter they perform best with full sun exposure; shaded trees produce little fruit.

Wind Tolerance:

Strong winds will damage branches so sheltered locations are preferred.

Pruning:

Mainly to remove any dead and damaged wood and maintain size. Remember when pruning that fruit is borne on 1-year-old wood. Thinning of fruit within the panicle will improve individual fruit size.

The Fruit:

The climacteric fruit is an ellipsoid or globose drupe weighing up to 400g but smaller with dwarf trees, and is borne on a long peduncle in bunches of a dozen or more. With ripening, skin colour changes from bright green to bright orange and the flesh turns a golden yellow or orange colour. The tough endocarp has irregular spines and fibrous protuberances and contains 1-5 flat seeds. The flesh has reasonable levels of Ca and vitamins A and C. Carbohydrate content is about 12%.

Fruit Production and Harvesting:

The season is fall to mid-winter. Fruit production usually begins in 3-5 years, with grafted plants taking only half this time and dwarf forms beginning as early as the 1st year. After flowering and fruit set, they take 5-6 months to mature; colour break then follows during the ripening process, with most fruit then falling from the tree over several weeks.The fruits drop while still green and hard and ripen slowly over several weeks.

Fruit Uses:

The fruit is eaten fresh and also used in juices, jams, jellies and in canned forms. The green fruit can be used in salads curries and pickles. Fresh, it is best while still firm and crisp when it is sub-acid and juicy with a fragrance and flavour frequently described as similar to pineapple. As the fruit softens the flesh becomes more fibrous and difficult to eat or cut.

Pests and Diseases:

Minimal.

Comments:

Ambarella could be planted for its ornamental value alone, but if you’re interested in the fruit the best bet is to go for a dwarf form. These begin fruiting much earlier and crop for a longer period each year. They’re also are a definite plus if space is limited.