Subtropical Fruit Choice Wide---
From Avocado to Tamarind
by Robert J. Knight, Jr., and Julian W. Sauls

 

Subtropical fruits number over a hundred and range from avocado and citrus to soursop and tamarind. Thus the information in this chapter has to be general rather than specific and you should seek more detailed advice from your county Extension office. Nurserymen can be most helpful too, as can experienced gardeners, garden clubs, or other specialized groups such as the rare fruit organizations active in Florida and California.

Fortunately, cultural requirements for most subtropical fruits do not differ from those of other shrubs, trees or vines grown for fruit, ornament, shade or other specialized use. In fact the outstanding ornamental value of most fruit crops fits them admirably for a dual role.

Because they come from many parts of the world with varied environmental conditions, subtropical fruit crops differ in the degree of cold they can withstand and in soil and moisture requirements. Some are adapted to warm-temperate conditions, and others are tropical plants which will tolerate brief cold spells and thus survive winters in the warmest parts of the continental United States.

When you select fruits to plant around your home, choose those known to grow well in your locality. Otherwise you may go to a lot of trouble to grow a plant that may prove disappointing despite your best efforts. Your own personal preferences, tempered by knowledge of what grows well in the area, should determine what you plant.

Most tree fruits should be planted 12 to 20 feet apart and away from the house, walks, drives, and power lines. Those tropical fruits listed as small trees or shrubs at the end of the chapter can be planted somewhat closer. Where there is significant danger of cold damage, plant subtropical fruits in the warmest part of the yard, which generally is the south side of the house.

Most failures in growing fruit trees at home can be attributed to poor transplanting or poor care. Commercial fruit growers routinely transplant fruit trees with almost no failures.

Good preparation of the planting hole is essential. Dig the hole only as deep as and about a foot wider than needed to accommodate the root system. Regardless of your soil type, it would probably benefit from the addition of liberal amounts of organic matter such as rotted manure, compost or peat.

For bare-root plants, prune off dead or damaged roots. Make a cone of soil in the center of the hole and set the plant on it, carefully spread. ing the roots out in the hole. For container-grown plants, remove the container and set the plant in the hole.

In either case, set the plant at the same depth it was growing in the nursery or container. Fill the hole three-fourths full of soil. Then fill with water to settle soil around the roots and eliminate air pockets. After the water drains through, finish filling the hole with Soil, then water again. A ring of soil a few inches high around the planting hole can be used to form a watering basin during the first year.

At planting, bare-root fruit trees should be pruned to balance the top with the reduced root system, which requires removing about a third of the top. Most people are reluctant to prune this heavily, but it's for the good of the tree. If you're unsure about doing the job right, have the nursery where you bought the tree do it for you. Container-grown plants are not usually pruned since they have an intact root system.

Training
Initial training of the fruit tree is done at planting to assure that the tree takes the desired shape. For example, the growing tips of branches are pruned off to force branching. Even so, most subtropical fruit trees are not trained appreciably, but simply allowed to develop naturally.

Mature trees are pruned to remove dead or damaged wood, or to eliminate limbs that may interfere with traffic in the yard. Such pruning can be done at any time of year.

Pruning cuts should be clean and close to the trunk to avoid leaving stubs which enable wood-rotting organisms to enter the tree. Protection with pruning paint is recommended if the cut is larger than an inch or so in diameter.

Subtropical fruit trees are not in such prominence that they require "special" fertilizers as yet. You can- not run down to the garden center and pick up a bag of "Kiwi Special" or "Atemoya and Cherimoya Food". Fortunately, subtropical fruits will grow just as well on a complete, balanced garden fertilizer such as 6-8-8, 10-10-10, or 12-12-12. However, if your area has alkaline soils or soils known to lack specific mironutrients such as iron, manganese or zinc, these may need to be supplied.

Newly planted trees should not have fertilizer until they resume active growth after transplanting. Then, fertilize sparingly and frequently until they mature and begin to produce fruit. Using 10-10-10 as an example, young trees should receive about a pound of fertilizer per year of tree age, that is, 1 pound in the first year, 2 in the second, and so on. Total fertilizer for the year should be divided into several applications so young trees receive some fertilizer every 2 to 3 months.

Mature, bearing trees can be fertilized at double that rate, or 2 pounds per year of tree age. Thus, a 10-year-old tree would receive 20 pounds per year, which would be split into 3 applications-early spring, early summer and early fall. Fertilizer can be spread on the ground under the tree and then watered in.

Lime may be needed in some cases to raise the soil pH so it is suitable for optimum tree growth. However, liming should be based on a soil test and recommendation from the county Extension agent. Occasionally, some fruit trees may need certain micro-elements, particularly in very sandy soils or alkaline soils. Micro-elements are included in some fertilizers and are also available in nutritional sprays which are applied separately as foliar (leaf) sprays. In all cases follow recommendations of your county agent.

Mulches
Mulches around fruit trees help in weed control and water conservation. They also reduce lawn mower damage to tree trunks since you don't need to mow close to the trees.

In some cases, organic mulches can lead to fertilizer deficiencies as the micro-organisms that decompose them rob nutrients the tree could use. They also contribute to increased cold damage by inhibiting radiation of ground heat to the tree. In other cases, organic mulches increase the incidence of diseases such as foot rot and root rot. For these reasons, we recommend clean cultivation instead of mulches for citrus, avocado, lychee and some other fruits.

Mulches from your yard could include leaves and grass clippings. Or you can obtain sawdust, wood chips, pine bark, gravel and other mulches from local nurseries. A lot of gardeners don't understand about watering plants. This is one reason why so many fruit trees die shortly after transplanting. Too little water causes the tiny root hairs to die, and the leaves then wilt for lack of water. On the other hand, too much water forces air from the soil, again causing the root hairs to die for lack of oxygen, and the leaves will wilt. For best results, water fruit trees infrequently but thoroughly.

Frequent, shallow waterings cause shallow rooting. A shallow-rooted fruit tree is subject to drought and poor growth. Consequently, when you water, water long and water well. Apply water only as fast as the soil can absorb it and keep watering until the soil is wet at least a foot down.

Newly transplanted trees need a good soaking every 2 to 4 days until they are well established. Mature trees need water every 7 to 12 days, depending on the climate and soil type. Since sandy soils don't hold much water, they require watering about once a week, while clay soils will go several days longer before drying out.

Fruit trees growing in the lawn area will compete with the lawn for fertilizer and water. In such situa- tions pay particular attention to needs of both tree and lawn. The tree will compete much more aggressively than the grass. The grass will soon begin to thin out and may disappear completely once the tree begins to create heavy shade.

Cold protection often is required for many subtropical fruits. Young trees are more susceptible to cold than large, mature trees, but also easier to protect. Banking a mound of soil around the trunk of a young fruit tree will keep the rootstock and trunk alive even if the top should freeze. Pull the bank down in spring after cold danger is past.

Small trees can be covered with blankets, paper or plastic to prevent freezing. Lawn sprinklers have been turned on trees, but too much water can cause problems for the root system and ice can cause limb breakage. In some cases, a frame covered with clear polyethylene can be built around the tree to form a mini-greenhouse. Some slow-burning heating materials are available and work quite well; check with your county Extension agent or nurseryman.

Most subtropical fruits have enough insect and disease problems to make growing them troublesome at times. You need to learn the potential pest problems and bow to control them. To do this requires a little effort on your part in order to be able to recognize the damage before it becomes serious, identify the insect or disease responsible, and take effective remedial action before the damage pro- gresses too far to control.

Containers
Many subtropical fruits can be grown in containers in areas where freezes occur each year. The size and mobility of the containers allows the plants to be moved indoors during winter months. Thus, the plants are treated pretty much as houseplants with regard to water, fertilizer, humidity, light, and pest control.

As with houseplants, water container plants infrequently but thoroughly. Take care to acclimate the plants to the different conditions when they are moved outdoors in spring or indoors in fall. Plants going outdoors should be moved to a shady spot for a couple of weeks before being exposed to full sunlight. Reverse this process when moving them indoors in fall.

When plants are indoors, put them in areas receiving the most natural light possible. Keep them away from heaters, doors and heating ducts. Because of lower humidity indoors, you need to increase the humidity around the plants, by misting or other means.

Growing plants in containers or patio tubs will reduce plant size due to the reduced volume of soil in which they're growing. Even so, the plant may soon grow too large to bring indoors. When this happens, prune back the plant severely.

Following is information about some fruits that can be grown in many parts of the Southern and Southwestern States. The letters Wt (Warm-temperate), St (Subtropical) and T (Tropical) are intended to give an approximation of temperature requirements of each species. However, other factors, such as amount of rainfall and the time of year that rain comes, will also determine whether a particular fruit can be grown in your area.

Avocado (Persea americana). St. T.
Shade tree with rough dark bark suitable for growing bromeliads and or- chids. More than one variety should be planted together for cross-pollination. Plant locally adapted varieties. Will not tolerate heavy, poorly drained soils.

Banana (Musa acuminata, Musa hybrids). T.
Rootstock may survive light freezes. Giant, treelike herb, planted for ornament where cold precludes fruiting. Many varieties have been introduced but the most widely grown are Cavendish (a commercial crop), Apple (sometimes called Lady- finger), and Orinoco (also called Horse banana and good for cooking). The starchy cooking banana called Plantain is very tender to cold.

Carambola (Averrhoa carombola). T.
Tree varying from small to large. Characteristic 5-angled fruit of yellow or deep orange color varies from sour to sweet and is pleasantly aromatic. Plant grafted varieties (Golden Star, Mih Tao). Cross-pollination aids fruit set.

Carob (Ceratonia siliqua). Wt.
Small tree with attractive dark green leaves that prefers a Mediterranean climate, very dry in summer with rains during winter. Trees may be male or female, so more than one should be planted to ensure fruiting. The brown, leathery pods are rich in sugar and furnish a chocolate substitute.

Cattley guava (Psidium cattleianum). St.
Shrub or small tree with beautiful mottled trunk and glossy dark green leaves. The small, round fruit, bright red or yellow-colored, is subacid in flavor and may be eaten fresh or made into jellies or jams. Plants grow readily from seed and are normally so propagated.

Feijoa (Feijoa sellowiana). Wt.
Shrub. Compact, cold-resistant and most attractive, selected varieties such as Coolidge fruit well without cross-pollination, but seedlings may not do so. Flowers are edible. Fruit can be eaten fresh, and makes a firm jelly.

Fig (Ficus carica). Wt.
Small tree. Adapted to a wide range of climates, fig will not tolerate nematodes. Where these are a problem, heavy mulching and occasional application of an approved nematicide, according to pre- scribed rules, will help. Lemon, Brown Turkey, and Celeste varieties are recommended.

Guava (Psidium quajava). T.
Small tree. Somewhat weedy unless pruned to shape it, the guava can be attractive, particularly when in bloom. Fruit of some seedlings and selected varieties is excellent for jelly, while that of varieties such as Ruby x Supreme and Indian Red is good to eat out-of-hand. Fruit flies are a problem where abundant.

Jaboticaba (Myrciaria cauliflora). St.
Shrubbery tree. Grows slowly but where well established produces abundant crops of black, grapelike fruit excellent to eat fresh or use in jellies or wines.

Kiwi, Yangtao (Actinidia chinensis). Wt.
Vine. Not successful in warmer parts of Florida, this deciduous species is sensitive to nematode damage. Flowers of named varieties (females, for example Hayward) must be pollinated in order to fruit, so a pollinator should grow nearby. Because of its excellent quality this fruit should be planted wherever it can be grown well.

Longan (Dimocarpus longan) T.
A lychee relative that bears clusters of attractive, smooth, golden brown, sweet-flavored fruit that is less tart than lychee fruit. The tree is less demanding as to soil and moisture than lychee, and makes a shade tree of stately proportions. Kohala, from Hawaii, bears large fruit ot good quality.

Loquat (Eriobotrya japonica). Wt.
Small tree. The dark green, deeply ribbed leaves of this tree combined with its tendency to produce fragrant creamy-white flowers over a period of months make the loquat a universally valued ornamental. The excellent fruit quality of grafted varieties such as Wolfe, Gold Nugget (Thales), and Champagne make these worth the effort needed to find them. Fruit is excellent eaten fresh, but may also be made into pie, jam, and jelly.

Lychee (Litchi chinensis). T.
Tree. Somewhat finicky, demanding slightly acid, well-drained soil, with abundant moisture and no salts in soil or water, this tree covered with its bright red fruit is a sight to remember where it grows well. Long popular in Southeast Asia, the fruit has many American devotees. It may be eaten fresh or dried like raisins. The most dependably productive varieties are Sweetcliff and Mauritius.

Mango (Mangifera indica). T.
Tree. Of the many existing varieties, take the time to select one that appeals to you: Carrie, Irwin, Glenn, Keitt, and Tommy Atkins are outstanding. Blooming trees can cause allergic reactions; do not plant near bedroom windows or air conditioner intake. The mango is one of the world's most popular fruits.

Passion fruits (Passiflora edulis, purple, and P. edulis f. flavicarpa, yellow). St. T.
Vines are ornamental. The purple-fruited form is sensitive to nematodes and soil-borne fungus disease, but withstands more cold than the yellow-fruited form, which is disease-resistant. Self-pollinating types should be planted where possible, otherwise fruit production may be sparse.

Pineapple (Ananas comosus). T.
Perrenial herb. This bromeliad makes an attractive house plant where outdoor temperatures are too low for it. The plant can be moved to a porch or patio during warm weather. Given enough light it will eventually flower, then produce a fruit of fine quality provided conditions are warm enough.

Pomegranate (Punica granatum). Wt.
Small tree that tolerates extremes of heat and alkaline soils, but thrives under a wide range of conditions. Needs full sun for best performance. Wonderful and Sweet are the varieties best known for their fruit quality. Other varieties are grown primarily as ornamentals.

Tamarind (Tamarindus indica). T.
Large tree related to the carob, with very acid fruit in pods. Pulp of the tamarind, an essential ingredient of many chutney recipes, also is used to make a refreshing ade-like drink. Where the climate is warm enough for it, this tree is easy to grow.

Annonaceous Fruits
Atemoya (Annona cherimola x A. squamosa). T.
Moderate-sized tree, a hybrid of the cherimoya and the sugar-apple, that combines the excellent fruit quality of the cherimoya with the fitness for low elevations of the sugar-apple. Flowers abundantly in warm weather, but may need to be hand-pollinated to assure fruit set. Desirable varieties are Kaller (African Pride) and Bradley. Others are under test.

Cherimoya (A. cherimola). St.
Small tree adapted to high elevations in tropical South America, producing a large green fruit with a sweet, delicately aromatic pulp that surrounds many smooth dark seeds. Does not grow well in southern Florida but is more successful in California where it withstands temperatures as low as 25F.

Soursop or guanabana (A. muricata). T.
Small tree, very sensitive to sudden cold spells, that bears a large, rough fruit with a refreshing acid flavor that is excellent in drinks and sherbets. Should be planted in a sheltered location.

Sugar-apple (A. squamosa). T.
Small tree that bears a soft-pulped, many-seeded fruit similar to the cherimoya but without that fruit's fine aroma. Grows well at sea level in southern Florida and other areas of similar climate.

Cactus Fruits
Indian fig
(Opuntia ficus-indica). Wt.
Large treelike cactus with smooth flat joints and few spines. Yellow flowers in spring are followed by large red or yellow fruit. Bristles can be irritating; handle fruit with care. Prefers a dry climate and does not thrive in humid situations.

Citrus
Calamondin (Citrus blancoi). Wt. St.
Small tree of great ornamental value that grows and fruits well in small containers. The fruits resemble small oranges but are acid and not good to eat out-of-hand. Flavor is excellent for drinks and marmalades.

Grapefruit (Citrus paradisi). St.
Medium to large-size tree, excellent for shade and for growing orchids and hanging plants, providing up to 300 pounds of excellent breakfast or juice fruit per year. Varieties include Duncan (white, seedy pulp, excellent flavor), Marsh (white, seedless) and Ruby (pink pulp, seedless).

Kumquat (Fortunella japonica). Wt.
Shrub or small tree, very cold-tolerant, extremely attractive when in fruit. Nagami is the most common variety, with oblong fruit, deep orange in color having a thick edible skin and an acid pulp. Adapted to candy making or use in marmalades.

Lemon (Citrus limon). T.
Small tree that remains in active growth all year and thus is less cold-resistant than the tangerine or even the orange. Of irregular growth habit, the lemon must be pruned from time to time to promote an attractive shape. Eureka, Lisbon and Villa Franca all bear similar fruit, of acceptable commercial quality; Eureka makes a smaller tree than the others. Novelties are Meyer with a less acid fruit, and Ponderosa, which bears very large, mild-flavored lemons.

Lime (C. latifolia). T.
Small tree that bears large, juicy green fruit useful in drinks, pies, and as a condiment. The most disease-resistant and dependably productive variety is the seedless-fruited cultivar known as Tahiti, Persian, or Bearss. Less resistant to disease and cold, and bearing smaller seedy fruit of a delectable flavor, is the Key or Mexican lime, C. aurantifolia. (A hybrid between the Key lime and the the Limequat produces a valuable acid fruit in areas too cold for the lime itself. Eustis fruits well in the open as well as in containers.)

Orange (C. sinense). St.
Tree of moderate size, probably the most popular of all citrus fruits, available in a number of varieties that ripen at various seasons. Hamlin is one of the earliest, ripening in November, followed by Pine- apple and Washington Navel, which ripen from December to February, and then by Valencia, which ripens in April or later and can be "stored on the tree" into the summer months.

Tangelo (C. reticulata x C. paradisi). St.
Tree, hybrid between tangerine and grapefruit, bearing fruit which combines characters from both parents. Vigorous and cold-resistant. Several varieties are available. Minneola and Orlando need to be planted near other citrus trees for cross-pollination. The Temple tangor (C. sinensis x C. paradisi) bears a sweet, juicy fruit similar to tangelos.

Tangerine (C. reticulata). St.
Tree of attractive growth habit, fairly resistant to cold, whose beauty is enhanced by the waxy, deep orange-colored fruit in season. Dancy ripens before Christmas, as does Clementine, which can be "stored on the tree" in good condition for months. Closely related are the cold-hardy and early dwarf Owari Satsuma, which ripens from October to Christmas, and the Kara, Honey and Kinnow mandarins.

Persimmons
Black-sapote (Diospyros digyna). T.
A tropical Mexican and Central American persimmon that grows well in southern Florida. The dark brown pulp is rich in vitamin C, and also a source of calcium and protein. It was important in the diet of Central America before Columbus.

Japanese persimmon (Diospyros kaki). Wt.
Small tree, attractive even when out of fruit with its large, hairy leaves; highly ornamental when the bright orange-colored fruit is ripening. Trees grafted on D. lotus or the native American D. virginiana are available. Fuyu bears fruit that is non-astringent even before fully ripe. Fruit of Hachiya and Tane Nashi is astringent until fully ripe, but then delectable. in dry climates, fruit may be sun-dried to make a fine-flavored product.

Robert J. Knight, Jr., is Research Horticulturist, Agricultural Research Service, Miami Fla, Julian W. Sauls is Extension Horticulturist, University of Florida, Gainesville..

Courtesy USDA

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