Soursop (Annona muricata)

Soursop (Annona muricata) is a tropical, evergreen tree that can grow up to 9 m tall. It produces the guanabana fruit, which ripens from mid-summer to mid-winter. The fruit is a spiky green pod with an aroma that smells like pineapple and tastes like a combination of strawberries and apples. The sweet yet sour fruit has a texture similar to that of a banana. The fruit can be eaten ripe or used to make juices and smoothies.

I. Appearance and Characteristics

Annona muricata is a species of the genus Annona of the custard apple tree family, Annonaceae, which has edible fruit. The fruit is usually called soursop due to its slightly acidic taste when ripe. Annona muricata is native to the Caribbean and Central America but is now widely cultivated – and in some areas, becoming invasive – in tropical and subtropical climates throughout the world, such as India.

The A. muricata fruit is generally called guanábana in Hispanic America, and the tree is a guanábano. Both tree and fruit were called catuche in some parts of Venezuela, but that word is currently less commonly used.

Annona muricata is a small, upright, evergreen tree that can grow to about 30 feet (9.1 m) tall.

Its young branches are hairy. Leaves are oblong to oval, 8 centimetres (3.1 in) to 16 centimetres (6.3 in) long and 3 centimetres (1.2 in) to 7 centimetres (2.8 in) wide. They are a glossy dark green with no hairs above, and paler and minutely hairy to no hairs below. The leaf stalks are 4 millimetres (0.16 in) to 13 millimetres (0.51 in) long and without hairs.

Flower stalks (peduncles) are 2 millimetres (0.079 in) to 5 millimetres (0.20 in) long and woody. They appear opposite from the leaves or as an extra from near the leaf stalk, each with one or two flowers, occasionally a third. Stalks for the individual flowers (pedicels) are stout and woody, minutely hairy to hairless and 15 millimetres (0.59 in) to 20 millimetres (0.79 in) with small bractlets nearer to the base which are densely hairy.

The petals are thick and yellowish. Outer petals meet at the edges without overlapping and are broadly ovate, 2.8 centimetres (1.1 in) to 3.3 centimetres (1.3 in) by 2.1 centimetres (0.83 in) to 2.5 centimetres (0.98 in), tapering to a point with a heart shaped base. They are evenly thick, and are covered with long, slender, soft hairs externally and matted finely with soft hairs within. Inner petals are oval shaped and overlap.

They measure roughly 2.5 centimetres (0.98 in) to 2.8 centimetres (1.1 in) by 2 centimetres (0.79 in), and are sharply angled and tapering at the base. Margins are comparatively thin, with fine matted soft hairs on both sides. The receptacle is conical and hairy. The stamens are 4.5 millimetres (0.18 in) long and narrowly wedge-shaped. The connective-tip terminate abruptly and anther hollows are unequal. Sepals are quite thick and do not overlap. Carpels are linear and basally growing from one base. The ovaries are covered with dense reddish brown hairs, 1-ovuled, style short and stigma truncate. Its pollen is shed as permanent tetrads.

The fruits are dark green and prickly. They are ovoid and can be up to 30 centimetres (12 in) long, with a moderately firm texture. Their flesh is juicy, acidic, whitish and aromatic.

Annona muricata is tolerant of poor soil and prefers lowland areas between the altitudes of 0 to 1,200 metres (3,900 ft). It cannot stand frost. The exact origin is unknown; it is native to the tropical regions of the Americas and is widely propagated. It is an introduced species on all temperate continents, especially in subtropical regions.

II. How to Grow and Care

Sunlight

Soursop thrives optimally in full sunlight conditions, benefiting from its intensity for the majority of the day. This exposure is key to its strong growth and fruit production. However, soursop also exhibits a degree of flexibility, tolerating partial sun. Such adaptability might slightly reduce growth rates and fruit yield compared to ideal conditions. As a tropical species, outdoor planting should be in areas where soursop can bask in ample sunlight yet remain protected from extreme weather that could stress the plant. Soursop’s broad leaves may adjust their orientation to optimize light absorption, a testament to its evolved light adaptability.

Temperature

Indoors, they prefer a warm, relatively moist environment, but especially in Winter, watch that your heat-pump doesn’t dry out their leaves. If outdoors or in a container on the porch, protect against frosts and extremes of cold (below 12C)

Watering

Thriving in its native tropical environment, soursop has adapted to withstand periods of high humidity and intermittent rainfall. This species is characterized by a preference for moist soil conditions, yet it exhibits resilience during drier intervals. Accordingly, soursop benefits from watering once every 1-2 weeks, maintaining a balance that reflects its habitat’s natural water cycle. Typically cultivated outdoors due to its size and climatic preferences, soursop demonstrates robust growth when seasonal rains complement regular irrigation schedules.

Soil

A well-drained fertile soil, rich in organic matter is ideal. Outdoors, similar but plant in deep soil and include sand, compost and even mulch. Basically, Soursop like similar growing conditions to the Cherimoya.

Fertilizing

Soursops are hungry for nutrients, so before adding fertilizer, loosen the surrounding top layer of soil and pour in your diluted liquid fertilizer, so that the roots can more easily utilize the nutrients and moisture. In Summer this can be done every 1-2 weeks.

Pruning

Prune the tree regularly to remove dead or diseased branches, to maintain shape and to promote healthy growth. Prune in late winter or early spring.

Propagation

Renowned for its distinct flavor and medicinal properties, soursop is chiefly propagated through sowing seeds. To enhance germination, use fresh seeds and plant in a well-draining, fertile substrate. Opt for partial shade to full sunlight locations and keep the soil consistently moist. Seedlings require tender care, being sensitive to both drought and water-logging. Gentle transplanting minimizes root disturbance, vital for the juveniles’ establishment and growth.

Transplanting

The commencement of warmer days in the dawn of spring is perfect for relocating soursop. Choose a sunny spot with well-draining soil. If moving an established plant, prune cautiously to balance root loss and ease transition.

Overwintering

Soursop thrives in tropical climates, where mild winters are customary. It naturally dodges frosting conditions, thus does not have innate winterization abilities. For gardeners, over-winter care should concentrate on providing warmth, either by relocating the plant indoors or using protective covers. Soil should be kept moderately moist, and natural light provision is crucial. Interaction with other cold-resistant species is not advised as soursop is sensitive to lower temperatures.

Repotting

For soursop, a sizeable shrub, repot every 2-3 years to support its robust growth. Ideal repotting is in late winter, ahead of its active phase. Select a large, deep pot to accommodate the root system, facilitating healthy development. Post-repotting, water sparingly until new growth appears, ensuring a smooth transition and vigorous yield.

III. Uses and Benefits

• Culinary uses

The flesh of the fruit consists of an edible, white pulp, some fiber, and a core of indigestible black seeds. The pulp is also used to make fruit nectar, smoothies, fruit juice drinks, as well as candies, sorbets, and ice cream flavorings. Due to the fruit’s widespread cultivation, its derivative products are consumed in many countries, such as Jamaica, Mexico, Brazil, Venezuela, Colombia, and Fiji. The seeds are normally left in the preparation, and removed while consuming, unless a blender is used for processing.

Soursop is also a common ingredient for making fresh fruit juices that are sold by street food vendors. In Indonesia, the fruit is commonly called sirsak and sometimes made into dodol sirsak, a sweet which is made by boiling the soursop pulp in water and adding sugar until the mixture caramelizes and hardens. In the Philippines, it is called guyabano, derived from the Spanish guanábana, and is eaten ripe, or used to make juices, smoothies, or ice cream. Sometimes, the leaf is used in tenderizing meat.

In Vietnam, this fruit is called mãng cầu Xiêm (Siamese soursop) in the south, or mãng cầu (soursop) in the north, and is used to make smoothies, or eaten as is. In Cambodia, this fruit is called tearb barung, literally “western custard-apple fruit”. In Malaysia, it is known in Malay as durian belanda (“Dutch durian”) and in East Malaysia, specifically among the Dusun people of Sabah, it is locally known as lampun. Popularly, it is eaten raw when it ripens, or used as one of the ingredients in ais kacang or ais batu campur.

Usually the fruits are taken from the tree when they mature and left to ripen in a dark corner, whereafter they will be eaten when they are fully ripe. It has a white flower with a very pleasing scent, especially in the morning. While for people in Brunei Darussalam this fruit is popularly known as “durian salat”, widely available and easily planted.

Soursop leaves are sold and consumed in Indonesia as herbal medicine. The leaves are usually boiled to make tea.

IV. Harvesting and Storage

Harvesting

The fruit is ready to harvest when it turns a dark green color and feels slightly soft to the touch. The fruit will ripen further after it is picked.

Storage

The fruit can be stored at room temperature for a few days or in the refrigerator for up to a week.