Jacaranda mimosifolia

Common name: Jakaranda

Other common names: Blue haze tree

Names in non-English languages: Spanish Portuguese

Description

Jakaranda originates from subtropical South America, its natural range extending from northern Argentina to southern Brazil.

It is a spectacular flowering tree up to 15 m (50 ft) in height, though is more typically 5 to 10 m (16 to 33 ft) tall with a slim, straight trunk supporting a wide-branching crown. The bark is grey and fissured.

The leaves are large, up to 50 cm (20 in) long and made up of numerous tiny green leaflets in an intricate, twice-feathered arrangement. They fall off the tree in the dry season to conserve water, leaving the branches bare until the rainy season arrives.

In spring, brilliant lavender-blue bell-shaped flowers bloom in clusters that are in stark contrast with the bare branches. Less common is a variety with white flowers.

The flowers are followed by small disc-shaped, woody seed capsules that become dark brown and dry, and when fully mature split open to release their seed, which are winged for wind dispersal.

Use

Jakaranda is widely cultivated in subtropical gardens and landscapes for its spectacular flowering display.

The wood is light- to medium-weight, in the 450 to 700 kgs per cubic meter (28 to 43 lbs per cubic ft) range, and its natural resistance to rot and decay is low, making it generally unsuitable for outdoor construction. 

Well-formed logs from large trees are sawn into planks for making boxes and crates or are sliced into thin sheets for decorative veneer. The branch-wood and small-diameter roundwood is pulped for plywood and particleboard, or is cut into lengths and dried for firewood. 

Climate

The tree needs cool, dry conditions prior to flowering for good flowering to occur, with the best flowering displays found in sub-humid to moderately humid subtropical and tropical mid- to high-elevation climates, generally areas with annual lows of 7 to 20 °C, annual highs of 20 to 35 °C, annual rainfall of 500 to 1400 mm and a dry season of 2 to 8 months. Although also cultivated in warmer and wetter climates, flowering is sparse to patchy at best.

Growing

New plants can be started from semi-hardwood cuttings or seed, which remain viable for up to twenty-four months under cold, dry, airtight storage. Trees from cuttings are preferred because they start to bloom at an earlier age.

Performs best on free-draining loam and sand soils of a moderately acid to alkaline nature, generally with a pH of 6.5 to 8.0 and on sites with full to partial sun exposure.

Problem features

It is listed as a serious weed in at least one reference publication and is classed as a weed of agriculture in Australia, due in part to its ability to disperse its seed on the wind over far distances. However, it is assessed as a low weed risk species for Hawaii and Florida, respectively by the Hawaii Pacific Weed Risk Assessment project (HPWRA) and the IFAS Assessment of Non-Native Plants in Florida's Natural Areas.

Over the course of the seasons, the spent flowers, leaves and seed capsules fall to the ground creating litter.

Where it will grow

References

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

  • Berni, C. A & Bolza, E. & Christensen, F. J. 1979, South American timbers - the characteristics, properties and uses of 190 species, Commonwealth Scientific and Industrial Research Organization (CSIRO), Division of Building Research, Highett, Victoria, Australia

  • Burke, D. 2005, The complete Burke's backyard : the ultimate book of fact sheets, Murdoch Books, New South Wales, Australia

  • Gilman, E. F. 1997, Trees for urban and suburban landscapes, Delmar Publishers, Albany, New York

  • Krishen, P. 2006, Trees of Delhi : a field guide, Dorling Kindersley Publishers, Delhi

  • 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.

  • Luna, R. K 1996, Plantation trees, International Book Distributors, Dehradun, Uttarakhand

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

  • 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, F. & Hay, R. 1982, A field guide to tropical and subtropical plants, Van Nostrand Reinhold Company, New York

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

  • Webb, D. B. 1984, A Guide to species selection for tropical and sub-tropical plantations, 2nd ed., Unit of Tropical Silviculture, Commonwealth Forestry Institute, University of Oxford, Oxfordshire

Articles, Journals, Reports and Working Papers

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

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