Tropicals & Tender Perennials: Tropical Garden # 24, 1 by Clemen

Clemen wrote:
More info:

Cultivars

No named cultivars are reported but there is considerable variation in the quality of fruit from different trees. The yellow-skinned types seem superior to the brownish, and, when well filled out, have thicker and juicier flesh. Seeds of a purple-skinned, purple-fleshed form, from Mexico, were planted in Florida and the tree has produced fruit of unremarkable quality.

Climate

The custard apple tree needs a tropical climate but with cooler winters than those of the west coast of Malaya. It flourishes in the coastal lowlands of Ecuador; is rare above 5,000 ft (1,500 m). In Guatemala, it is nearly always found below 4,000 ft (1,220 m). In India, it does well from the plains up to an elevation of 4,000 ft (1,220 m); in Ceylon, it cannot be grown above 3,000 ft (915 m). Around Luzon in the Philippines, it is common below 2,600 ft (800 m). It is too tender for California and trees introduced into Palestine succumbed to the cold. In southem Florida the leaves are shed at the first onset of cold weather and the tree is dormant all winter. Fully grown, it has survived temperatures of 27º to 28ºF (-2.78º to 2.22ºC) without serious harm. This species is less drought-tolerant than the sugar apple and prefers a more humid atmosphere.

Soil

The custard apple does best in low-lying, deep, rich soil with ample moisture and good drainage. It grows to full size on oolitic limestone in southern Florida and runs wild in light sand and various other types of soil in the New and Old World tropics but is doubtless less productive in the less desirable sites.

Propagation

Seed is the usual means of propagation. Nevertheless, the tree can be multiplied by inarching, or by budding or grafting onto its own seedlings or onto soursop, sugar apple or pond apple rootstocks. Experiments in Mexico, utilizing cherimoya, llama, soursop, custard apple, Annona sp. Af. lutescens and Rollinia jimenezii Schlecht. as rootstocks showed best results when custard apple scions were side-grafted onto self-rootstock, soursop, or A. sp. Af. lutescens. Custard apple seedlings are frequently used as rootstocks for the soursop, sugar apple and atemoya.