The Mamey Sapote (Calocarpum sapota) has been grown and has fruited in Florida for probably close to a century. Yet it is strange how few trees of this Central American fruit are to be found here. However, with our recently-acquired Cuban population which runs well over a quarter million, interest in this sapodilla (Manilkara zapata, Syn. Achras zapota L.) relative has taken on a new look.
Seedlings in small containers bring $6.00 or more, and small grafted plants up to $45.00 each. The demand for the fresh fruit so greatly exceeds the supply that a price of $2.00 or more a pound is common. One Miami grower has had thousand-dollar annual crops off a single tree!
The Mamey Sapote is indigenous to the American tropics where it makes a large tree, attaining heights of 65'. It has a thick trunk and heavy branches. The leaves, dark green on top and lighter green beneath, could be said to resemble those of the loquat (Eriobotrya japonica) but are much larger, reaching 15" or more in length. These form clusters toward the ends of the branches. The small white flowers appear in the fall by the thousands, encircling the mature wood of the branches. The first two or three annual blooms to appear usually result in no fruit set. Vegetatively propagated, the Mamey can come into bearing at an age of about six or seven years upon attaining a height of 12'.
When young, the plant is tender and should be protected from frost and high winds. Freezing temperatures, much below 28°F. and of moderate duration, can seriously injure even mature trees. In the writer's opinion, the most serious drawback to cultivation of the Mamey is its slowness to come into bearing, which can be 15 years for a seedling. Fortunately, grafting or air-layering can reduce this waiting time by half or even more. Under favorable conditions, the Mamey makes a large tree in Florida. The writer's three bearing trees, the largest of which is 34' in height at an age of twenty years, have not been appreciably damaged by hurricanes.
The Mamey Sapote bears its main crop in summer and early fall, although some fruit can be had nearly year round. This fruit is usually large, from one to five pounds and take about 12 months on the tree to mature. In outline, it can vary from top-shaped to oval to nearly round. It has a brown, rough-textured exterior like coarse sand paper would be if tiny pieces of cork were substituted for the normal grit. The thick rind surrounds a reddish pulp in which one to four large, hard, brown, smooth seeds are embedded.
Under south Florida's growing conditions, the. Mamey does fairly well on most soils except for marl and requires no special fertilizers. On poor rocky, alkaline soils it tends to suffer from zinc, iron and possibly manganese deficiencies. In the grove, 1½ lbs. neutral zinc and 1½ lbs. manganese can be added to 100 gallons of water and applied as a foliar spray. Geigy 138 iron chelate mixed with water and applied as a ground drench under the tree has been found to give favorable results in correcting this deficiency. A preventive spray schedule is recommended, rather than waiting for the symptoms to appear. The above applications can be applied in the fall before dormancy and again in late spring after a flush of growth.
In the Dade County area, the tree is subject to attack by Cuban May beetle (Phyllophaga bruneri, Chapin) which eats the leaves and can be quite destructive, especially to small trees.
The Mamey Sapote can be propagated by seed, air-layer (marcot), side veneer graft and approach graft. The 3" to 4" long seeds should be potted up as soon as possible after removal from the fruit because after a few days' exposure to dry air, they can lose their viability. Frequently, seeds commence their germination while still in the fruit, and the sprouting roots tightly surround a part of the hard, smooth shell. By planting the seed vertically, pointed end down, the roots will be headed downward in the right direction. If the top of the seed is about level with the soil surface, the roots will have more room to grow downwards before striking the bottom of the container and making a 90-degree bend.
Most people have difficulty in getting Mamey grafts to take. An alternative would be to marcot the plant. This should be done using sphagnum moss with a plastic wrap, preferably in the summer, but in any event, three months or more prior to leaf drop. This occurs in Florida in the spring when new foliage replaces the old. Air layers on the tree during this leaf change period all die when mature existing leaves fall off and new ones fail to develop. The best time for air-layering is in the late spring or early summer after the new leaves have matured. Marcots put on at this time frequently root by the end of the third month, while those made in winter are seldom successful.
In grafting, a foot or so of ½" to ¾" diameter scionwood should be girdled by removing a ¾"-wide strip of bark one to several months prior to removal, depending on the time of year, summer being best. All the leaves should be removed from the girdled part of the branch except the terminal three or four leaves. After the previously-ringed graftwood has swollen to about one fourth again its original diameter, it can be removed. If it is left on during the leaf change period in spring, it will die. At this stage, the scionwood will be covered with buds, so it can be cut up into 3" lengths and each piece, including the terminal bud, used to make a side veneer graft. With this method, the writer usually gets about four out of five grafts to take.
Approach grafting, either by using a potted plant or a germinating seedling suspended in sphagnum moss-filled plastic bags tied up among the branches, has proven fairly successful.
In Florida, we have four or more varieties that have been vegetatively propagated. The Rare Fruit Council International Yearbook lists two that are probably the largest-fruited. These are the 'Magana', a single-seeded introduction from El Salvador with fruit that can run up to five pounds, and the 'Cuban No. 1', whose fruit also is unusually large, mostly single-seeded and can reach 9" in length. Of these two, the 'Magana' is preferred because of its tendency to bear at an earlier age. It has been noticed that the 'Magana' can ripen fruit from bloom in less than a year on the tree, while the 'Cuban No. 1' takes over a year.
To describe the fruit of the various varieties would be like slicing apples open and trying to describe the pulp. While the outside configuration of the fruit varies from elliptic to oval to occasionally round, the outside color of all Mamey Sapotes is the same. The flesh differs only in color, from light yellow-orange to a dark red. It is considered by the writer impossible to tell from outward appearance when the Mamey Sapote, any variety, is ripe, for the brown-colored exterior layer of the skin undergoes no color change upon ripening. This means that the fruit must either be left to fall upon the ground after ripening, or the surface of the skin on the underside of the fruit must be scratched with the fingernail to reveal the color of the flesh just beneath the surface. If it is green, it should be left on the tree for further ripening. If it is light pink color, it may be picked and brought into the house for further ripening. In a day or two it will be soft and ready to eat.
How good does the rich fruit taste? Some say it reminds them of ... sweet potato, but for the Cuban, no other fruit that God created can compare with it.
DATE: January 1981
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