Black Sapote

What is black sapote?

Black sapote is an evergreen fruit tree from the ebony family, Ebenaceae, and belongs to the same genus as the persimmon. Its common name is misleading: "sapote" comes from the Nahuatl word for soft, sweet fruits and is used for several unrelated plants. The white sapote is a citrus relative, the mamey sapote belongs to the Sapotaceae.

The fruit looks unremarkable while it hangs: round to slightly flattened, 5 to 12.5 cm across, with a shiny green skin and a large green calyx. Only when fully soft does the flesh turn dark brown to black and take on the texture of a pudding. Each fruit holds up to ten flat brown seeds according to Morton, and is often seedless.

Origin and growth

Black sapote is native to both coasts of Mexico and to the forested lowlands of Central America. Spanish ships carried it to the Philippines and the Moluccas early on, from where it spread further in the tropics. Botanists today generally accept the name Diospyros nigra; the long-used Diospyros digyna is treated as a synonym.

The tree has leathery, glossy, dark green leaves and an oblong crown. The University of Florida describes medium trees of about 7.6 to 9 m and large ones of up to about 24 m; in cultivation it usually stays medium-sized. Many trees are either male or female, some carry bisexual flowers, and pollination is done by insects.

Requirements

Black sapote is a plant of warm, frost-free climates. According to the University of Florida, young trees are damaged or killed at about -1 °C and mature trees at about -2 °C. It grows in most well-drained soils, including sand and limestone with a high pH, tolerates temporary flooding better than many fruit trees and is only moderately drought tolerant. Full sun and the warmest available spot are recommended. In its homeland it grows from dry forests to alluvial clay that floods, and in Mexico it is cultivated up to about 1,500 to 1,800 m.

Fruit, use and harvest

The fruit is picked hard and mature, when the skin turns from shiny to dull green and the calyx lobes bend upwards, and then left to soften for 3 to 14 days. Ripe flesh is eaten fresh or mixed into drinks, ice cream and cakes. Morton gives a vitamin C content of about 190 mg per 100 g of flesh.

Unripe fruit should never be eaten: it is astringent, irritant and bitter and was used as fish poison in the Philippines. Seedlings take five or six years to flower and do not come true; good varieties are grafted.

In the food forest

In a food forest black sapote can grow into a medium to tall evergreen tree and in the long run belongs in the upper tree layers. In its youth it is sensitive and benefits from the protection of nurse trees against frost and wind, as long as it is not kept in deep shade, since the University of Florida recommends full sun for fruiting. A thick layer of mulch keeps the root zone cool and moist through the summer. Its evergreen foliage shades the ground all year and adds leaf litter.

In the Mediterranean climate

Documented experience with black sapote in the Mediterranean is scarce. It is grown mainly in Mexico, Central America, the Philippines and in subtropical Australia, and in Europe the fruit is hard to find. The decisive limit is frost: a single night at -2 °C can damage even an older tree, and seedlings in southern California did not survive. Where it has a chance, then, is in frost-free coastal sites, warm walls and sheltered slopes, ideally with young trees kept in pots and protected in the first winters. Summer drought is the second hurdle, since the tree needs regular water while fruit is developing. Black sapote is not on the EU list of invasive alien species, and no invasive tendency is known.

Propagation and care

Seed germinates readily but gives unpredictable trees. Grafting onto seedling rootstock secures a fruiting variety. Young trees need shelter from frost and wind, regular water in summer and generous mulch. Pruning keeps the crown open and the tree manageable.

How Terra Humana understands it

Black sapote is one of the tropical guests at Sa Medada whose place is still open. It stands for a question that runs through the whole project: how far the line of what grows here shifts when soil, shade and mulch soften the extremes. Terra Humana wants to answer that question with care, without promising more than the plant can give, and treats every winter that black sapote comes through as a small piece of evidence.