This week we look at more of the interesting tropical fruit trees that we are able to grow in southern Florida.
Cashew Apple (Anacardium occidentale)
The Cashew Tree is an attractive, mid-sized species with a broad canopy. It produces large, leathery green leaves and yellowish-pink flowers. Native to arid northeastern Brazil, it was discovered in 1578 by Portuguese colonists. The first sighting by Europeans of the tree in fruit must have raised eyebrows, because what they beheld was a fleshy red or yellow structure with a seed hanging beneath it like a fat arboreal comma. But the nut seemed to be useless for human consumption, as the poor colonists who ate it tended to end up in a heap by the side of the road. Consequently, the initial attraction of the tree was its colorful, fleshy, sweet-tasting receptacle, which looks like a fruit, but is really part of the fruit stalk. It has come to be called Cashew Apple. Known formally as an accessory fruit or pseudofruit, it grows on the seed and does not precede it.
Through trial and error, the Europeans learned that the seed was edible if roasted so that the toxic shell could be cracked off. Nevertheless, commercial trade in cashew ‘nuts’ didn’t start until the 1920s. After ripe cashews fall from the tree, they are hand-collected and dried in the sun. They are then roasted, after which they are shelled by machine or by hand. In the nut trade, the leading cashew producers are widely separated—Viet Nam, Nigeria, India, Brazil and Indonesia. Cashew trees are quite tolerant of drought; in fact, dry periods are required to stimulate flowering. In southern Florida, they should be planted on well-drained sites and fed with a fertilizer for acid-loving trees.
Blackberry Jam Fruit (Rosenbergiodendron formosum)
Rosenbergiodendron formosuam, f/k/a Randia formosa, is a native of Central and South America. It is a small evergreen shrub––trainable as a small tree––that matures to 4-5 ft. tall. As a member of the family Rubiaceae, it is a gardenia relative, and its 1½-2 in. white, tubular, star-shaped flowers produce a nice fragrance. And that’s not the end of the show. After pollination, olive-shaped yellow fruits develop. Inside each mature fruit are two cells containing a seed wrapped in soft, black pulp. Eaten out of hand, the pulp is sweet, a virtual match to blackberry jam.
R. formosum has other attributes, too. It begins blooming at a fairly early age, 12-18 months, and flowers and fruits in the fall/winter season, when other fruit trees are barren. New blossoms appear as the earliest fruits are maturing. Even a small specimen can yield a couple of dozen fruits. The species can flower and fruit in filtered light in addition to full sun. A slow grower, it is quite amenable to container culture. R. formosum is not difficult to grow, but it’s important to keep a couple of cultural requirements in mind: (1) Provide ample moisture and good drainage, but reduce watering during the coldest times of the winter. (2) Apply acidic fertilizers for optimum appearance and growth.
Swiss Cheese Plant (Monstera deliciosa)
This sturdy aroid has been described by one prominent botanist as “probably the finest foliage plant ever introduced into horticulture.” But it is even more than that, because it produces a delicious fruit that combines the tastes of pineapple, banana and even mango! The vine was introduced to England in 1752, but in the indirect way by which many tropical plants became distributed around the planet, the fruit of Monstera, despite the species’ New World origin, did not debut in the United States until 1874.
While the leaves of a young M. deliciosa are solid and heart-shaped, giving no early clue to any exceptional qualities, as the plant develops, the glossy, symmetrical leaves become much larger, split at the edges, and develop holes, often oblong, near the center. The mature leaf gives rise to the species’ widely-known common name, Swiss Cheese Plant. Under ideal conditions, the leaves of Monstera can exceed 3 ft. in length.
Monstera is a liana, i.e., a woody vine, native from Mexico to Panama. In the wild it may reach 70 ft., climbing trees to reach into the rain forest canopy. But M. deliciosa does not need to be grown only as a liana in the landscape. Its versatility allows it to be maintained as an impressive mid-size hedge. One of its best applications is to soften fences or walls at the edges of a property, and it possesses a wide range of light and water tolerance once established.
The plant’s aromatic fruit bears a mild resemblance to a corn cob. The “cob” bears hard green, hexagonal, cap-like scales that cover the fruits. The scales begin to pop off the fruits as they ripen. Monstera fruits are not only eaten fresh, but are used to flavor beverages, jams, baked goods, ice cream. sauces, stir fries and syrups.
Tamarind (Tamarindus indica)
The tamarind, a tree native to Africa, is a good example of a plant so valuable to humankind that it was long ago distributed to other lands where it naturalized, ultimately coming to be considered native there. So strongly did the Tamarind Tree come to being associated with India that when it reached Persia and Arabia, it was called ‘tamar hindi,’ or Indian date. From that erroneous term emerged the name tamarind!
Just as an ornamental, this species has a lot going for it. It makes a very attractive shade tree, characterized by a stocky, short trunk which supports a broad, dome-like crown. In some places around the world, it reaches 80-100 ft. in height, but in southern Florida 50 ft. is more common for mature trees. It has a moderate growth rate. The branches of older trees take on a drooping habit. Of particular value in our area is the high wind resistance of the tamarind’s trunks and branches. The crown is densely foliated with fairly delicate, bright green, pinnate leaflets. Except during the driest of winters, the tree remains evergreen.
Cooked tamarind fruit pods—from immature to fully ripe—have very significant uses in tropical cuisine. The pulp surrounding the seeds has a major role in the preparation of various curries and chutneys, as well as certain brands of Worcestershire sauce. In both the Old World and New World, a beverage—tamarind ade—has long been made from the fruit. In more recent times it has been concocted as a carbonated drink. The pulp is also made into jelly, jam, ice cream and sherbet. Tamarind syrup is a popular product in Puerto Rico.
Mysore Raspberry (Rubus niveus)
Only one species of raspberry has proven dependable in southern Florida. It is the Mysore Raspberry. R. niveus is a fairly large, sprawling shrub that can reach 10 ft. or more in height. Its cylindrical stems are pubescent (downy) when young, and bear hooked thorns. Its compound leaves possess serrated leaflets that are dark green on top and whitish and fuzzy on the undersides. The flowers of the Mysore Raspberry are pink to reddish-purple, about a half inch across, and clustered.
Of course, the most desirable feature of the Mysore Raspberry is its fruit. Shaped much like that of the red raspberry, that is, rounded-conical, with a flat base, it is considerably larger, 1/2 to 3/4 in. in diameter. It is red when immature, but darkens to purple-black upon ripening. The ‘bumps’ typical of raspberry fruit are more accurately known as drupelets. Luckily, the small seeds of R. niveus are inoffensive. And the taste is wonderful—sweet and juicy. Not only is the fruit a good source of Vitamin C, but one researcher considers it to be “a valuable natural antioxidant that has an immense scope as an effective source to cure skin diseases, wounds, and tumors.”
The Mysore Raspberry seems to be tailor-made for the soils of southern Florida; it thrives in alkaline limestone or in acidic sand. Supplemental irrigation should be supplied during the dry season. The best fruiting occurs when plants are grown in less than full sunlight. And while this species fruits all year long, the best combination of quality and size happens in the winter and spring. Accordingly, a homeowner may want to prune plants significantly in late spring.
All species described above are in stock at Richard Lyons’ Nursery.