Hawaii is known for our lush tropical gardens but much of our land especially on the leeward side is desert. There are many delectable fruits that actually do best where conditions are hot and dry. Figs, pomegranates, papaya and dates are just a few that come to mind, but mangoes are by far the most popular. These fruit have become part of our Hawaiian cuisine and represent the amazing food fusion of our multicultural islands.
Mango trees will grow almost anywhere on the island from sea level to 2000 feet elevation, but where conditions are too wet the fruit is often damaged by fungus diseases. There are literally scores of varieties that can produce delicious fruit from early spring to late fall.
Mango trees have been grown by early cultures for over 5,000 years in the Hindo-Berma region of tropical Asia. The origin is believed to be somewhere near present day Malaysia or in the Thailand, Cambodia and Vietnam area. Hundreds of varieties have been developed over the millennia. Some of the most popular were bred by the University of Hawaii and University of Florida in the 20th century. Trees grown from seed may carry the traits of the parent but take 10 or more years to produce fruit. Sometimes seedlings will bear inferior fibrous or turpentine tasting fruit, but some may actually produce fruit of superior quality. That is how new varieties may be discovered and named.
If you already have one or more mango trees in your garden, you may have noticed some things that reduce the quantity or quality of your fruit. Here are some tips. If we have wet weather when the trees begin to flower in December, the blossoms will abort due to one or more fungus diseases. If this happens, the trees will tend to flower again, but most commercial growers will apply a recommended fungicide to keep the flower set and get an early crop.
As the fruit matures we may have wet weather that will make ideal conditions for anthracnose fungus to streak the fruit. This may also be avoided by applying a fungicide. The main insect that damages fruit is the mango seed borer. This causes the flesh to be mushy around the seed. Sanitation is the key by removing rotting fruit from the ground. Another cause of mushy flesh is calcium deficiency in our volcanic acid soils. Addition of dolomitic lime with the fertilizer schedule will avoid this problem.
Trees may be fertilized two to three times per year with a formula low in nitrogen and high in phosphorus and potassium. This year many trees are flowering in May as well so we are likely to get a double crop unless the rains cause conditions ideal for Botrytis. This fungus damages flowers and they die before producing fruit.
Another easy fruit for dryer or well drained soils is actually not a tree but a big herbaceous plant. The origin of Carica papaya as it scientifically known is considered to be Mexico. Now it is grown worldwide in the tropics and subtropics.
Papaya plants are a natural for almost any garden. They are prolific and nutritious as well. Probably no other plant supplies the home gardener so much for so little effort. This tropical America tree-like plant will grow and produce fruit the year around with a minimum of care.
Green, unripe papayas are high in papain that helps digestion. The leaves are also high in papain and used in cooking. Ripe fruits are high in calcium, vitamin A and C.
Your garden can supply a generous amount of these delicious fruits. By following modern methods, you may grow many other tropical fruits as well. But one of the best is papaya.
Start with good plants, proper attention to fertilizer, moisture needs, and keep insects under control. You’ll harvest some very good fruit that will repay you for your trouble.
There are several varieties, from the big watermelon fruit to the small Solo types. Most folks prefer the bisexual or Solo strain of papaya. This type produces a high percentage of top quality fruit. Seeds from the large watermelon types produce male, female and bisexual trees. Most of the male trees must be eliminated as soon as they are detected. They are identified by means of their bloom stems. These are sometimes up to more than a foot in length and have many flowers. Female blooms are produced close to the stem but have no pollen bearing stamen. Bisexual flowers have both ovary and stamen, thus can self pollinate.
Occasionally, garden shops and nurseries offer Solo papaya plants for sale, and the gardener who needs a few plants will do well so buy his plants rather than to attempt to grow them from seed. For larger numbers of plants, you may grow seed from selected fruit. Seed order forms are available from the University of Hawaii Cooperative Extension Service.
The papaya is a relatively short-lived herbaceous plant, reaching a height of fifteen, or more feet in five years. A top quality plant should produce over 150 pounds in a two-year period. But commercial growers often harvest up to 300 pounds from a plant during a two-year period. After that, the plant becomes so tall it is difficult to pick fruit. Production drops rapidly.
The papaya requires large amounts of fertilizer for best production. Spread the fertilizer out over an area roughly covered by the leaves.
A papaya plant won’t thrive in soil that is too dry or poorly drained. Young plants must be kept well watered until they are established, then watered every four or five days during the dry season. Mulching will help to conserve moisture. In wetter areas of the island, irrigation will only be necessary during drought periods.
Pests can give papaya growers trouble. The worst pests are aphids, mites and fruit flies. There has been no insecticide that will give satisfactory control of the fruit fly in dooryard plantings. Harvesting fruit before they become over ripe will help keep damage to a minimum. Sanitation is also important. Do not leave fruit to rot in the garden thus allowing fruit flies and other unwanted pests to proliferate.
Mites, almost microscopic spider-like creatures, sometimes cause visual damage. This does not usually affect the taste of the fruit. Nematodes, microscopic worms that feed on papaya roots are also a problem. Good fertilization practices and mulching will minimize nematode damage.
With little effort your papaya plants should reward you with abundance.
Norman Bezona is professor emeritus, University of Hawaii College of Tropical Agriculture and Human Resources.
