Chrysophyllum cainito

Common name: Star apple

Other common names: Star plum

Names in non-English languages: Philippines Malaysia

Description

Star Apple is a fruit-bearing tree originating from the Caribbean, its natural range extending along the chain of islands from Cuba, through the Cayman Islands, Jamaica and Hispaniola to Puerto Rico.

A medium-sized tree, it may reach heights of up to 30 m (100 ft) in natural forest habitats, though it is more commonly 15 to 20 m (50 to 65 ft) tall. On open sites, it develops a short trunk supporting a densely branched rounded crown, made up of wide-spreading branches that droop at the end, creating a weeping appearance. The bark is dark brown, rough and fissured.

Leaves oval to elliptical, dark lacquered green on top and copper-brown underneath, their contrasting colouration adding visual interest to the tree. They remain on the tree where the dry season is short but fall to the ground where it is long and pronounced.

Flowers tiny, purplish or greenish and bisexual, having both female and male parts. Flowering appears to be associated with decreasing day length that starts in late summer and continues into late autumn or early winter. 

The fruit ripen around three to four months after fruit-set, usually from winter to late spring, or through to early summer in its native range. They are round, about the size of a tennis ball or larger and come in smooth, purple or green skinned varieties. A star-shaped pattern is revealed when it is cut in half crosswise, which has led to the name 'Star Apple' being given to both the fruit and tree. The seed are oval, largish, and glossy dark brown to near black.

Use

The tree is cultivated primarily for its fruit, which is eaten fresh out-of-hand or used in fruit salads. The fruit are usually cut in half and the sweet, soft, jelly-like pulp scooped out with a spoon, avoiding taking any of the pulp close to the rind, as this has a sticky latex, especially in fruit that are not fully ripe. The fruit do not continue to ripen after being harvested, so are best left on the tree until fully ripe.

The leaves with their contrasting colouration adds ornamental interest to gardens, and their dense arrangement provides much needed shade from the tropical sun.

Star Apple trees produce a medium-weight wood, averaging out at around 700 kg per cubic meter (44 lbs per cubic ft), with low natural resistance to decay. This puts it in the non-durable hardwood class, limiting its suitability for any outdoor or in-ground construction work. When available, it is mostly used for turnery and occasionally for making furniture and cabinets.

Climate

Grows and fruits naturally in moderately humid subtropical and tropical climates, generally frost-free areas with annual lows of 15 to 25 °C, annual highs of 25 to 35 °C, annual rainfall of 900 to 3000 mm and a dry season of 3 to 6 months.

Although Star Apple trees also grow well in wetter climates with no dry season, flowering is usually poor due to fungal attack, resulting in low fruit production. As well, trees may fail to produce flavoursome fruit in areas where the average low of the warmest month falls below 21 °C (70 °F).

Growing

New plants are usually started from seed, which remain viable for up to six months and germinate readily. However, seedling trees may take up to ten years to produce fruit, so vegetative propagation is preferred. Cuttings and air-layering (circumposing) methods are the most commonly practised and the trees start to flower and bear fruit when around three to five years old.

Mature trees in South Florida produce up to 68 kg (150 lbs) of fruit in a season but this may be low compared to regions with warmer, tropical climates.

Performs best on free-draining loam, sandy-loam and loamy-sand soils of a moderately acid to alkaline nature, generally with a pH of 5.0 to 8.0, and on sites with full to partial sun exposure.

Problem features

Star Apple is listed as a weed in at least one reference publication, but there does not appear to be any record of it anywhere  as a serious weed, despite its widespread cultivation throughout the tropics.

Where it will grow

With irrigation or groundwater

References

Books

  • Adams, C. D. 1972, Flowering plants of Jamaica, University of the West Indies, Mona, Greater Kingston

  • Chudnoff, M. 1984, Tropical timbers of the world, Forest Service, U.S. Department of Agriculture (USDA), Washington, D.C.

  • Gargiullo, M. B & Magnuson, B. L. & Kimball, Larry D. 2008, A field guide to plants of Costa Rica, Oxford University Press, Oxford

  • Janick, J., & Paull, R. E. 2008, The encyclopedia of fruit & nuts, CABI Publishing, Wallingford, Oxfordshire

  • Jensen, M. 1999, Trees commonly cultivated in Southeast Asia : an illustrated field guide, 2nd ed., Food and Agricultural Organisation of the United Nations (FAO) Regional Office for Asia and the Pacific (RAP), Bangkok

  • Little, E. L. et al. 1964 and 1974, Common trees of Puerto Rico and the Virgin Islands (2 volumes), Forest Service, U.S. Department of Agriculture (USDA), Washington D.C.

  • Macmillan, H. F. 1943, Tropical planting and gardening : with special reference to Ceylon, 5th ed, Macmillan Publishing, London

  • Martin, F. M., et al. 1987, Perennial edible fruits of the tropics : an inventory, U.S. Dept. of Agriculture (USDA), Agricultural Research Service, U.S. Government Printing Office (GPO), Washington, D.C.

  • Morton, J. F. & Dowling, C. F. 1987, Fruits of warm climates, Creative Resources Systems, Winterville, North Carolina

  • Page, P. E. 1984, Tropical tree fruits for Australia, Queensland Department of Primary Industries (QLD DPI), Brisbane

  • Queensland Department of Primary Industries and Fisheries (QLD DPI) 2008, Queensland tropical fruit : the healthy flavours of North Queensland, Brisbane

  • Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

  • Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

  • Scheffer, T. C & Morrell, J. J. 1998, Natural durability of wood : a worldwide checklist of species, Forest Research Laboratory, Oregon State University, Corvallis, Oregon

  • Schubert, T. H. 1979, Trees for urban use in Puerto Rico and the Virgin Islands. U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans

  • Wilder, G. P. 1911, Fruits of the Hawaiian Islands rev. ed, Honolulu: The Hawaiian gazette co. ltd.

Articles, Journals, Reports and Working Papers

  • Subhadrabandhu, S. 2001, Under-utilized tropical fruits of Thailand, Food and Agriculture Organisation of the United Nations (FAO), Regional Office for Asia and the Pacific (RAPA), Bangkok

  • Walkar, Tad, et al. Dispersal modes of woody species from the northern Western Ghats, India. Tropical Ecology 53.1 (2012).

  • Watson, B.J., & Moncur, M. 1985, Guideline criteria for determining survival, commercial and best mean minimum July temperature for various tropical fruit in Australia (Southern Hemisphere), Department of Primary Industries Queensland (DPI QLD), Wet Tropics Regional Publication, Queensland

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