Common name: Golden dewdrops

Golden dewdrops is a flowering ornamental originating in tropical American and now widely cultivated throughout the tropics.

Typically a multi-stemmed shrub 2 to 3 m (7 to 10 ft) tall, though occasionally a small tree up to 6 m (20 ft), it develops a densely branched, wide-spreading canopy of slender, arching and drooping branches. As the plant matures, the branches become armed with sharp thorns, though some varieties are thornless. The bark is light-grey, smooth at first becoming fissured with age.

Depending on the variety, the leaves are small and glossy, either dark green, yellowish or variegated, with the margins smooth on young leaves becoming saw-toothed as they age.

Flowering is induced by a rise in humidity brought on by the rainy season, which arrives with the transition from spring to summer in its native range. Depending on the variety, the flowers are small, tubular and light purple, blue or occasionally white. They are clustered on long, drooping spikes at the branch tips and are followed by small, golden-yellow, berry-like fruit from summer to autumn. 

Use

Golden dewdrops is a popular hedge and barrier plant on account of its dense growth and sharp thorns. Its showy flowering and fruiting are also appreciated, with the bonus of attracting nectar seeking butterflies, hummingbirds and fruit-eating birds to the garden.

Honeybees are observed vigorously working the flowers, but there does not appear to be much information published on its importance as a honey plant. It has moderate salt tolerance, which makes it suitable for growing in coastal gardens. 

General interest

Chloroform extracts of the fruit, leaves and stems were found in scientific studies in India to be an effective repellent against the Common Southern Mosquito (Culex quinquefasciatus) [Asian J Pharm Clin Res, 2019, 12(6), pp.317-320], as well as being detrimental to the development of its larvae [International Journal of PharmTech Research, 2009, 1(4), pp.1709-1713.].

Climate

Although naturally adapted to coastal conditions, it grows and flowers reliably in sub-humid subtropical and tropical lowland to mid-elevation climates, generally areas with annual lows of 9 to 25°C, annual highs of 19 to 35°C, annual rainfall of 800 to 1800 mm and a dry season of 7 months or less.

Growing

New plants can be started from cuttings or seed, which easily germinate. It is tolerant of a wide range of soils, including limestone but grows best in rich, free-draining loam soils. It is susceptible to many insect pests.

Problem features

The fruit are highly poisonous to humans causing intestinal irritation, with consumption reported to be fatal in some cases. Symptoms include drowsiness, nausea, vomiting, fever and convulsions.

Birds are attracted to the fruit and disperse the seed outside of cultivation. It is assessed as a high weed risk species for Hawaii by the Hawaii Pacific Weed Risk Assessment (HPWRA) project.

Books

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

• Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London

• Francis, J. K. 2004, Wildland shrubs of the United States and its territories: Thamnic descriptions, U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry, Río Piedras, San Juan, Puerto Rico & Rocky Mountain Research Station, Fort Collins, Colorodo

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

• Iremonger, S. 2002, A guide to plants in the Blue Mountains of Jamaica, University of the West Indies Press, Kingston, Jamaica

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

• Morton, J. F. 1971, Exotic plants, Golden Press, New York

• Oakman, H. 1995, Harry Oakman's what flowers when : the complete guide to flowering times in tropical and subtropical gardens, University of Queensland Press, St. Lucia, Queensland

• Perry, B. 2010, Landscape plants for California gardens: an illustrated reference of plants for California landscapes, Land Design Publishing, Claremont, California

• Rauch, F. D. & Weissich, P. R. 2000, Plants for tropical landscapes : a gardener's guide, University of Hawaii Press, Honolulu

• The Garden Section of the Woman's Club of Havana 1958, Flowering plants from Cuban gardens : Plantas floridas de los jardines cubanos, Criterion Books, New York

Articles, Journals, Reports and Working Papers

• Johnson, A. & Johnson, S. 2006, Garden plants poisonous to people, New South Wales Department of Primary Industries (NSW DPI), Orange, New South Wales

• Morton, J.F. 1964, Honeybee Plants of South Florida, Proceedings of the Florida State Horticultural Society, Vol 77:415-436.

• Queensland Department of Agriculture and Fisheries (Australia) 1990, Weed and pest animal fact sheets, Brisbane