June Plum (Spondias dulcis)

June plum is a tropical tree that produces an edible fruit popular in the cuisines of Southeast Asia, the Pacific Islands, and the Caribbean. Its leaves are eaten in countries including Thailand and Costa Rica. It is grown both commercially and as a domestic fruit tree. In smaller gardens, its size can be controlled by growing it in a container.

I. Appearance and Characteristics

Spondias dulcis (syn. Spondias cytherea), known commonly as June plum, is a tropical tree, with edible fruit containing a fibrous pit. In the English-speaking Caribbean it is typically known as golden apple and elsewhere in the Caribbean as pommecythere or cythere. In Polynesia it is known as vī.

This fast-growing tree can reach up to 20 m (66 ft) in its native range of Melanesia and Polynesia; however, it usually averages 10–12 m (30–40 ft) in other areas. Spondias dulcis has deciduous, pinnate leaves, 20–60 cm (8–24 in) in length, composed of 9 to 25 glossy, elliptic or obovate-oblong leaflets 9–10 cm (3.5–3.9 in) long, which are finely toothed toward the apex. The tree produces small, inconspicuous white flowers in terminal panicles. Its oval fruits, 6–9 cm (2.4–3.5 in) long, are borne in bunches of 12 or more on a long stalk. Over several weeks, the fruit fall to the ground while still green and hard, then turn golden-yellow as they ripen. According to Morton (1987), “some fruits in the South Sea Islands weigh over 500 g (1 lb) each”.

II. How to Grow and Care

Sunlight and Temperature

June plum trees prefer full sun, but also grow well in partial sun. They need at least 4-6 hours of sunlight each day. Plants can be grown in USDA zones 4-11 if they are potted and brought inside during the frost. If planted in the ground, they can be grown in USDA zones 9-11.

Spondias dulcis grows best in humid tropical and subtropical climates. Trees are very sensitive to frost. A heavy frost will cause dieback of entire branches or potentially kill the tree. When freezing temperatures are in the forecast, bring potted trees inside or cover in-ground trees with frost fabric. Excessive heat above 100℉ can cause sunburn in immature trees. Cover immature trees with a light shade-cloth or protect the trunk with a sleeve.

Watering

Originating from the tropical Pacific Islands, june plum thrives in humid conditions and has adapted to withstand brief periods of drought. This species is accustomed to a consistent level of moisture, reflective of its rainforest origins. For optimal health, june plum should be watered once every 1-2 weeks, maintaining soil that is moist but not waterlogged. As an outdoor plant often found in warmer climates, june plum’s growth cycle is influenced by rainfall patterns, requiring less supplemental watering during the rainy season.

Soil

June plum grows well in all types of soils as long as they are well-draining. They will survive under poor nutrition, but grow more vigorously and produce more fruits when fed properly. Trees grow well in acidic to slightly alkaline soils with a pH of 5.5-7.5. They prefer more acidic soils.

Fertilizing

Apply 10-10-10 two to four times per year when the tree is actively growing especially during flower and fruit production.

Pruning

Immature trees need to be carefully monitored as they are known to fruit themselves to death. Flowers and fruit will need to be thinned on younger trees otherwise heavy fruits can cause new branches to split. Fruits also consume a lot of nutrients, so having a lot of fruits on a young tree will stunt its growth.

Dwarf trees tend to grow bushier and require pruning to maintain the desired height and shape of the tree. Standard trees need to be pruned to avoid any overlapping branches and to maintain the size and shape. Flowers do not require old growth to develop, so there is no concern about pruning off flowering branches.

During a heavy frost, branches may die back and will need to be pruned off in the spring to stimulate new growth. Fruits should drop off naturally, but any old, rotten fruits should be removed to avoid disease and fruit flies.

Propagation

Spondias dulcis can be propagated by seed, hardwood cuttings, air layering, or grafting.

Propagating by seed is easy, but fruit characteristics may be variable. Luckily trees are fast-growing and begin producing fruits at a young age. Some will even begin to produce after about a year.

Hardwood cuttings and air-layering are the preferred methods of propagation because it is easy and the fruit characteristics will be the same. Trees can also be grafted on the same species rootstock or other Spondias rootstock. However, cuttings and air-layering are the preferred methods because the process is much easier.

Transplanting

June plum thrives when transplanted from early to late spring, as mild temperatures and ample moisture help establish roots. Choose a sunny, well-drained location. Transplanting during this season supports robust growth and reduces transplant shock.

Pests and Diseases

Common Pest

The Caribbean fruit fly is a small orange-brown fly that lays eggs inside the fruits making the fruits undesirable when the eggs hatch. Open wounds in the fruits can also lead to fruit rot. The best way to prevent fruit flies from laying eggs in the fruit is to bag the fruit on the tree for protection.

Scale insects are round flat insects that come in a variety of colors from green to red to brown. They are usually found on twigs and branches. Scales are mostly a concern because of their secretion of honeydew. Honeydew leads to the development of sooty mold, which can cover the leaves of the tree preventing it from photosynthesizing. It’s very common for scales to go unnoticed until the black sooty mold begins to cover the leaves. If the issue becomes extreme, growth can be affected. Natural enemies should keep populations under control, but oil sprays can be used to knockdown scale populations that get out of hand.

Thrips are small, yellow to orange insects that feed on new leaves and flowers. Their damage can cause scarring on the leaves and developing fruits. Chemical treatment on Ambarella trees is not typically needed. Spraying the leaves with water will help deter thrips.

Mites are small eight-legged arachnids that cause stippling damage on leaves. Plants are more susceptible to mite infestation when stressed. High levels of damage can cause leave drop and overall decline. Maintaining healthy plants is the best defense against mites. If treatment is necessary, oil sprays are effective.

Common Diseases

Root rot may occur if the tree is overwatered or if it is not planted in well-draining soil. Excessive water will drown the roots and allow for root diseases to easily infect the tree. Prevent root rot by planting in a good location and by using best irrigation practices.

Fruit rot is caused by fruit fly infestation creating an open wound that allows for pathogens to infect the fruit. Avoid fruit rot by preventing fruit fly infestations by bagging the fruit on the tree.

III. Uses and Benefits

Spondias dulcis is most commonly used as a food source. It is a very nutritional food containing vitamin B, C, and A. In West Java, its young leaves are used as seasoning for pepes. In Costa Rica, the more mature leaves are also eaten as a salad green though they are tart. However, it is most commonly used for its fruit.

The fruit may be eaten raw; the flesh is crunchy and a little sour. According to Boning (2006): “The fruit is best when fully colored, but still somewhat crunchy. At this stage, it has a pineapple-mango flavor. The flesh is golden in color, very juicy, vaguely sweet, but with a hint of tart acidity.” In Indonesia and Malaysia, it is eaten with shrimp paste, a thick, black, salty-sweet sauce called hayko in the Southern Min dialect of Chinese. It is an ingredient in rujak in Indonesia and rojak in Malaysia. The juice is called kedondong in Indonesia, amra in Malaysia, and balonglong in Singapore.

The fruit is made into preserves and flavorings for sauces, soups, braised and stews. In Fiji it is made into jam, its leaves are used to flavour meat. In Samoa and Tonga it is used to make otai. In Sri Lanka the fruit is soaked in vinegar with chili and other spices to make acharu. In Vietnam the unripe fruit is eaten with salt, sugar, and chili, or with shrimp paste. Children eat the fruit macerated in artificially sweetened licorice extract. In Jamaica, it is mostly considered a novelty, especially by children. It can be eaten with salt or made into a drink sweetened with sugar and spiced with ginger.

In Barbados, the ripe fruit is eaten naturally, or sprinkled with a bit of salt, or dipped in the ocean’s natural slightly salty water while at the beach. It is also used to make juice in Grenada and Saint Lucia. In Trinidad and Tobago, it is curried, sweetened, salted, or flavored with pepper sauce and spices. In Cambodia it is made into a salad called nhoam mkak (/ɲŏam məkaʔ/ ញាំម្កាក់). In Suriname and Guyana, the fruit is dried and made into a spicy chutney, mixed with garlic and peppers. In Thai cuisine both the fruits and the tender leaves are eaten.

IV. Harvesting and Storage

Harvesting

June plums are great to eat unripe and ripe, so harvesting depends on personal preference. Harvesting can begin as soon as the fruits reach a full size of about 2.4-3.5 inches long. The fruits can be picked green or golden yellow. When picked green, the flavor will be much more mellow. If allowed to ripen, the fruits will develop a tangy flavor.

Since the fruits grow in a cluster of at least a dozen, the entire cluster can be removed with pruners. For large trees, they can be shaken off the branches.

Storing

Green fruits should be stored at room temperature until ripe. Ripe fruits can be stored for several days in the refrigerator.

For long term storage, fruits can be made into jam. They can also be juiced or made into a sauce and kept in the freezer.