Outside of Mexico the black sapote is little known; in that country, however, it is one of the popular fruits and is grown from sea-level up to elevations of 5000 or even 6000 feet. Unfortunately, the dark color of the flesh makes the fruit somewhat unattractive to those not familiar with it, but its large size, relative freedom from seeds, and its good quality make it a worthy tropical rival of the subtropical kaki or Japanese persimmon.
In the Mexican lowlands the black sapote, if grown on deep, rich, and moist soil, becomes a large and handsome tree, ultimately reaching 50 or 60 feet in height. In regions where the climate is cool or the soil is not favorable, it may not grow higher than 25 or 30 feet. The branchlets are dark colored, and the leaves elliptic or oblong in outline, usually obtuse at the apex, commonly 4 to 8 inches long, and bright green and shining. The flowers are small and white and resemble those of the kaki. They are polygamous, i.e., some of them possess both stamens and pistils and others are staminate. The oblate fruit, which has a conspicuous green calyx around the stem and is somewhat obscurely ribbed or lobed, is 2 to 5 inches in diameter and olive-green in color. The pulp which lies within its thin skin is soft, unctuous, dark chocolate brown in color, and of sweet flavor similar to that of the kaki but scarcely so pleasant. The seeds, one to ten in number (occasionally none), are oval, compressed, and about 3/4 inch long.
Plate XIX. The sapodilla (Achras Sapota).
William Philip Hiern, a recent monographer of the Ebenaceae, following the botanist Manuel Blanco, considers the black sapote to be indigenous in the Philippine Islands. Other authorities, however, hold that its native home is in Mexico, and perhaps also in the West Indies. Many American plants were carried to the Philippines in the early days by the Spanish galleons which plied between Acapulco and Manila, and conversely, certain Philippine plants were brought to America. Elmer D. Merrill 1 observes regarding the black sapote: "Rarely cultivated, flowering in March; of local occurrence in the Philippines. Introduced from Mexico at an early date, and apparently formerly much more common than now." The existence of an Aztec name, tliltzapotl (if Manuel Urbina is correct in believing that this name was applied by the Aztecs to Diospyros Ebenaster) would argue an ancient cultivation in America, though it would not necessarily indicate that the species is indigenous here. But on the whole, the evidence seems to weigh heavily in favor of an American, as opposed to an Asiatic, origin.
At the present time, the black sapote is cultivated on a very limited scale in the West Indies and in Hawaii, and rarely in the East Indies. It has been planted at Miami, Florida, where it gives promise of being quite successful. It is sometimes injured by frost in that region, but danger from this source seems to be no greater than with the mango. Although many seedlings have been planted in California, they have failed to survive the winters, even when grown in the most protected situations. The common name of the fruit in Porto Rico is guayabote or guayabota; in Hawaii it has been called black persimmon; while the usual terms in Mexico are zapote negro and zapote prieto.
1 Flora of Manila.
The black sapote is eaten fresh. It is more highly esteemed by Europeans when the pulp is beaten with a small quantity of orange or lemon juice and served as a dessert. It should be chilled thoroughly before serving.
In its climatic requirements the species must be considered tropical, yet it will succeed in regions occasionally subject to temperatures of 28° or 30° above zero. Young plants, however, are killed by freezing temperatures, and for this reason it is necessary in Florida to protect them during the first few winters. In Mexico the species grows both in regions subject to heavy rainfall and those which are extremely dry, but in the latter it requires abundant irrigation. It is most commonly grown at elevations from 0 to 2000 feet, which indicates that it prefers a warm climate. It prefers a deep, moist, sandy loam, but has made fairly good growth in Florida on shallow sandy soil.
Like other fruits, the black sapote is grown in the tropics as a dooryard tree and is not often planted in orchard form. Little is known, therefore, regarding the cultural methods which will best suit it. Young trees are set in the open ground when one to two feet high, and should be spaced (if in the tropics and on deep soil) not closer than 40 feet, or 25 feet if in a subtropical climate (such as that of Florida) and on poor soil. Propagation is usually effected by means of the seeds, which retain their viability for several months if kept dry. They should be sown 1/2 inch deep in flats or pots of light loamy soil, and will germinate in about a month if the weather is warm. When three inches high, the plants may be transferred to three-inch pots. Their growth is slow and they require one to two years to reach suitable size for transplanting to the open ground.
P. J. Wester has found that the species may be propagated by shield-budding in much the same manner as the avocado and the mango. Using this method it is possible to perpetuate choice varieties which originate as chance seedlings. Wester says briefly : "Use mature, but not green and smooth, petioled budwood; cut the buds about an inch and a half long; insert the bud at a point where the stock is green or brown before it becomes rough."
Seedling trees do not come into bearing until they are five or six years of age. Even more time than this has been required in Florida. Mature trees usually bear regularly and heavily. The ripening season in the Mexican lowlands is July to September, somewhat later in the tierra templada or region which lies between 2500 and 4000 feet. If taken from the tree when mature and shipped immediately, the fruit may be sent to distant markets; but once it has softened (usually three to six days after it is picked), it is difficult to handle because of its thin delicate skin and the large mass of soft pulp.
No horticultural varieties have as yet been established. Seedlings differ noticeably in the size and character of their fruits, and it will be worth while to search out the best ones and propagate them by budding. Fruits 1 1/2 pounds in weight are seen at Tehuantepec, State of Oaxaca, Mexico.