Common name: Blue mahoe

Blue mahoe is a medium-sized timber and landscape tree native to the Caribbean Islands of Jamaica and Cuba, where it occurs mainly in humid tropical forests.

Depending on the growing conditions, it grows at a fast to moderate rate to heights of up to 35 m (115 ft), though it is more typically 15 to 20 m (50 to 65 ft) tall.

The trunk is straight and slender, up to 40 cm (15 in) in diameter and supports a rounded crown of ascending branches. The bark is grey or light brown, on young trees smooth, becoming fissured with age.

The leaves are heart-shaped and large, 10 to 20 cm (4 to 8 in) long and wide, on top dark green with veining and occasionally soft hairs, underneath light green. They remain on the tree in all seasons and cast a deep shade on the ground below.

The flowers are hibiscus-like and large, 8 to 10 cm (3 to 4 in) across, with five orange-yellow or orange-red petals that wither to deep red. They are borne singularly and bloom year-round in constantly humid climates but are short-lived, lasting only a day.

Fertilised flowers are followed by finely hairy, egg-shaped seed capsules 3 to 4 cm (1.2 to 1.6 in) long. Yellow-green when young, they mature to yellow-brown and have small, finely hairy seed up to 0.5 cm (0.2 in) long inside.

Use

Blue mahoe trees produce a medium-weight wood, averaging around 620 kgs per cubic meter (39 lbs per cubic ft), with high natural resistance to rot and decay. This categorises it as a durable hardwood, suitable for indoor and outdoor construction.

The heartwood is grey-blue or grey-green and attractively figured with purple, metallic-blue and green streaks, causing it to resemble highly polished marble.

Well-formed logs are sawn into planks used mostly for high-quality furniture and cabinets, joinery or millwork, flooring, musical instruments, turnery items, gun stocks and carvings.

The bark stripped from young trees is supple and traditionally used for making rope, but this practice is now discouraged as it damages the tree.

Blue Mahoe is sometimes planted as a street, shade or landscape tree for its shapely form, eye-catching foliage and showy flowers.

General interest

Blue Mahoe is highly regarded in Jamaica and has been declared the country's national tree.

Climate

Grows naturally in humid tropical lowland to mid-elevation climates, generally areas with annual lows of 15 to 25°C, annual highs of 25 to 35°C, annual rainfall of 1400 mm to 3800 mm and a dry season of 3 months or less. However, it has its best development in areas with annual rainfall of 1600 mm or more.

In Jamaica, Blue Mahoe occurs at elevations from near sea level up to 1200 m (4000 ft), in areas where the average low of the warmest month is 16°C (61°F) or above.

Growing

New plants are usually started from seed, obtained by harvesting mature seedpods before they open and then drying them in the sun until they split. The seed remain viable for four to six months, after which their viability declines.

The seed are sown in individual containers with a free-draining potting mix, and the seedlings cared for in a nursery under shade until they are planted out, when about 40 to 60 cm (1.3 to 2 ft) tall.

Blue mahoe performs best on fertile, moist, free- to slow-draining clay-loam, silt-loam, loam and sandy-loam soils of an acid to slightly alkaline nature, generally with a pH of 4.5 to 7.5, and on sites with full to partial sun exposure.

Problem features

Blue mahoe produces many viable seed which fall to the ground and germinate readily. However, there does not appear to be any record of it anywhere as a serious weed or invasive species. And this is despite its introduction to many non-native areas as a plantation timber tree.

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

• Brady, G. S. & Clauser, H. R & Vaccari, J. A. 2002, Materials handbook : an encyclopedia for managers, technical professionals, purchasing and production managers, technicians and supervisors, 15th ed., McGraw-Hill, New York

• C.A.B. International 2013, The CABI encyclopedia of forest trees, CABI Publishing, Wallingford, Oxfordshire

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

• Fawcett, W. 1891, Economic plants, An index to economic products of the vegetable kingdom in Jamaica, Jamaica Government Printing Establishment, Kingston

• Francis, J. K. 1998, Tree species for planting in forest, rural, and urban areas of Puerto Rico, U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry, Río Piedras, Puerto Rico

• Francis, J. K. and Liogier, H. A. 1991, Naturalized exotic tree species in Puerto Rico, General technical report SO-82, USDA Forest Service, Southern Forest Experiment Station, New Orleans

• Francis, J. K. et al. 2000, Silvics of Native and Exotic Trees of Puerto Rico and the Caribbean Islands, Technical Report IITF-15, USDA Forest Service, Rio Piedras, Puerto Rico

• Hill, A. F. 1952, Economic botany : a textbook of useful plants and plant products, 2nd ed, McGraw-Hill, New York

• Little, E. L. & Skolmen, R. G. 1989, Common forest trees of Hawaii (native and introduced), Agricultuural Handbook No. 679, Forest Service, U.S. Department of Agriculture, Washington, D.C.

• 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.

• Longwood, F. R. 1962, Present and potential commercial timbers of the Caribbean: with special reference to the West Indies, the Guianas, and British Honduras, U.S. Dept. of Agriculture Forest Service, Washington, D.C.

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

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

• 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