Plant of the Month: Exotic tropical fruit for Kona gardens

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If you are ready to venture into the world of exotic tropical fruit, consider planting a tree from the annonaceae or custard-apple family. Several tasty species are available and grow well here in Kona. Each of them has slightly different conditional preferences but all can be maintained at less than 20 feet tall and will produce flavorful fruit with numerous uses.

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If you are ready to venture into the world of exotic tropical fruit, consider planting a tree from the annonaceae or custard-apple family. Several tasty species are available and grow well here in Kona. Each of them has slightly different conditional preferences but all can be maintained at less than 20 feet tall and will produce flavorful fruit with numerous uses.

The large custard-apple family includes more than 125 genera and 2,000 species, most of which are native to the tropics. In Hawaii, both the annona and the rollinia genus are popular for their exotic flavors. Four members of the family are especially well-suited to our weather conditions and are locally available. Though opinions vary on the best tree or tastiest fruit in this group, the information presented here may help you decide which you’d like to plant.

Many declare the rollinia deliciosa to be the flavor queen of the lot. This tree will grow quickly at elevations from 300-3,000 feet as long as is in deep soil and gets adequate water. Under ideal conditions it can grow as much as 10 feet in a year and will usually produce fruit in its third year. Rollinia flowers have an unusual structure with three wing-like protrusions. Once pollinated each flower produces a single ovoid-shaped fruit. Though the skin has a rough, bumpy appearance, it is actually quite thin and easily bruised. The fruit should be picked when it starts to turn from green to yellow. Its creamy white flesh has a wonderful sweet, slightly acid flavor that can be enjoyed spooned out fresh or pureed for an ingredient in a dessert soufflé or ice cream. A UH CTAHR publication on this fruit can be found at http://www.ctahr.hawaii.edu/oc/freepubs/pdf/F_N-21.pdf.

The largest fruit in this group is the soursop, Annona muricata. This tree does best at elevations above 300 feet where it will not be affected by salt spray. It grows well in soil that drains well but it is sensitive to strong winds and needs protection in windy areas. It is the most drought tolerant tree in this group but does best with heavy mulching to hold moisture close to its shallow root system. The soursop flower is another odd specimen with a triangular shape and thick, fleshy petals that open for pollination. Once pollination takes place the soursop begins to develop into a light green oblong fruit with soft spines. The Hawaii size record for soursop is a 12-inch long fruit that weighed over 8 pounds. The pulp can be eaten fresh, pressed to make juice or blended to make smoothies or fruit soup. Though the fruit is delicious, soursop’s recent popularity is due to largely to its anecdotal reputation as a cancer fighter. Both the fruit and the leaves are touted as cancer preventing. You can find more information on soursop’s medicinal uses at various sites online. An informational publication on growing soursop is available at http://www.ctahr.hawaii.edu/oc/freepubs/pdf/F_N-22.pdf.

Cherimoya trees (Annona cherimola) are a very popular choice for Hawaii as the trees can grow and fruit at elevations up to 5,000 feet and will do well as low as 800 feet. Best grown at upper elevations, cherimoya enjoys rich soil that drains well. Cherimoya flowers are also botanically interesting. They first appear as small female flowers with three drooping petals. They then open, becoming male flowers which produce pollen. Successful pollination of the female flowers can be improved by inter-planting with soursop or by hand pollination. Instructions for hand pollination can be found at http://forums.gardenweb.com/discussions/2178045/how-to-cherimoya-pollination. The fruit of this species varies in size, shape and appearance depending on its variety. With either smooth indentations or bumpy protuberances, the fruit can weigh two pounds or more where conditions are ideal. Tasty as a fresh fruit, cherimoya can also be pureed and used as an ingredient in desserts like mousse.

The atemoya, (Annona × atemoya) is another member of the custard-apple family that grows well here and produces tasty fruit. This tree is actually a hybrid of the sugar-apple (Annona squamosa) and the cherimoya. Atemoya trees do well at lower elevations and have an interesting ladder-like growth habit making them ideal for growing in small, narrow spaces. The small green atemoya flowers begin as female flowers and then open to become male flowers. Pollination is best achieved by planting two trees near one another to increase the possibility of male pollen reaching a female flower. Hand pollinating can increase your yield. If you want to try it, use the same instructions as those for hand pollinating cherimoya. The resulting fruit has thin warty pale-green skin that bruises easily. The flavor is somewhat similar to others in this group: juicy, smooth, slightly sweet with a little tartness. Some compare the atemoya’s flavor to a vanilla flavored pina colada. Though most annona trees grow well from seed, seeds from atemoya will not grow true to the species. You are advised to purchase grafted trees from a reliable nursery or use the seeds to grow rootstock and graft a scion from a tree that produces good fruit.

All of these trees are native to various locations in South America but are now grown throughout the tropics. Out of their native environments, pollinators may be rare or nonexistent. In Hawaii, a few pollinators do exist but good fruit production is greatly enhanced by hand-pollination as well as companion planting near others in the annona family. A cherimoya planted near a soursop will produce more fruit than a solitary plant of either variety. Because the resulting fruit on these trees can be heavy, maintaining strong lower branches is advised. Pruning into a “wineglass” shape with an open center provides the best structure for them. Keeping the trees low helps facilitate hand pollination and harvest. The fruit produced by this group of trees maintains a light green color as it grows. A tinge of yellowing on the fruit indicates ripening. Harvesting at this stage is advised. The fruit will become soft to the touch and fully ripe in a few days. Rollinia fruit is completely yellow when ripe. The fruit from all of these trees is delicious but must be handled carefully as their skin is thin and they bruises easily. If they need to travel, wrap and pack them carefully to prevent excessive bruising. All but the atemoya can be grown successfully from the oval black seeds found inside the fruit.

Pests and diseases are rare when these trees are planted in sunny locations and are well maintained. Many diseases and root problems can be avoided by ensuring the trees have an adequate water supply in fertile soil that drains well. Wet, soggy soil encourages fungal diseases. Mulching in the root zone and regular additions of a balanced fertilizer will definitely encourage good health for all of the Annonaceae family varieties. For more information on the family go to http://www.hawaiifruit.net/Cherimoya.htm. The information in this publication generally applies to all the trees covered here.

Several local nurseries carry one or more of these plants or can order them if requested. Some are available through Hawaii Tropical Fruit Growers. Contact Executive Director Ken Love at 323-2417 or ken@mycoffee.net for availability information. Plant a few of these annona varieties on your land and plan to enjoy the flavor treats they offer.

This article has been reviewed for accuracy by tropical fruit specialist Ken Love. Diana Duff is a plant adviser, educator and consultant living on an organic farm in Captain Cook.

Gardening Events

Saturday: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Farmer Direct Markets

Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Wednesday: “Sunset Farmers Market” 2 p.m. to sunset at the north makai corner of the Kmart parking lot.

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

Sunday: “South Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook

Tuesday–Saturday: “U-Pick greens and produce” 10 a.m. to 4 p.m. Tropical Edibles Nursery, Captain Cook.

Plant Advice Lines

Anytime: konamg@ctahr.hawaii.edu

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Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu at 322-4892

Mondays, Tuesdays and Fridays: 9 a.m. to noon at UH CES at Komohana in Hilo at 981-5199 or himga@hawaii.edu

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