Rainfall. The plant does not tolerate drought well. For good production, it needs a fairly constant source of water. In Latin America, the tree thrives under more than 1,200 mm rainfall during the growing season. As noted, high humidity assists pollen set, and a dry period during harvesting prevents water-induced damage to fruit. Also, water stress just before flowering may increase flower (and hence fruit) production.
Altitude. The cherimoya does best in relatively cool (but not cold) regions, and is unsuited to the lowland tropics. (In equatorial regions it produces well only at altitudes above 1,500 m.)
Low Temperature. The plant is frost sensitive and is even less hardy than avocados or oranges. Young specimens are hurt by temperatures of −2°C.
High Temperature. The upper limits of its heat tolerance are uncertain, but is is said that the tree will not set fruit when temperatures exceed 30°C.
Soil Type. Cherimoya can be grown on soils of many types. The optimum acidity is said to be pH 6.5–7.5. On the other hand, the tree seems particularly adapted to high-calcium soils, on which it bears abundant fruits of superior flavor. Because of sensitivity to root rot, the tree does not tolerate poorly drained sites.
Related Species. The genus Annona, composed of perhaps 100 species mostly native to tropical America, includes some of the most delectable fruits in the tropics. Most are similar to the cherimoya in their structure. Examples are:
Sugar apple, or sweetsop (Annona squamosa). Subtropical and tropical. The fruit is 0.5–1 kg, and yellowish green or bluish. It splits when ripe. The white, custardlike pulp has a sweet, delicious flavor.
Soursop, or guanabana (A. muricata). This evergreen tree is the most tropical of the annonas. The yellow-green fruit—one of the best in the world—is the largest of the annonas, sometimes weighing up to 7 kg. The flesh resembles that of the cherimoya, but it is pure white, more fibrous, and the flavor, with its acidic tang, is “crisper.”
Custard apple, or annona (A. reticulata). This beige to brownish red fruit often weighs more than 1 kg. Its creamy white flesh is sweet but is sometimes granular and is generally considered inferior to the other commonly cultivated annonas. However, this plant is the most vigorous of all, and types that produce seedless fruits are known.