Araucaria bidwillii: Bunya-Bunya

The Araucariaceae family includes only two genera — Araucaria and Agathis — whose distribution is confined to the southern hemisphere. They are very ancient conifers from the evolutionary aspect and mostly large trees with branches arranged in whorls. The strikingly straight trunks together with the regular arrangement of the branches give the trees a rather stiff look. The leaves of araucarias are persistent, alternate, needle-like, with a single vein (the leaves of agathis are wider, with many parallel veins). The male and female cones usually grow on different trees (the trees are dioecious). At one time araucaria forests were widespread in Europe and it was not until the late Tertiary period that they were forced back to the southern hemisphere.

The species is from the coast of Queensland. In its native habitat it is a large tree with a straight trunk and regular horizontal branches. The leaves are needle-like, about 1 to 2 cm (½ to ¾ in) long, and furnished with a keel on the underside, this being the principal characteristic distinguishing this species from A. angustifolia. In cultivation, even in good conditions, it reaches a height of only 2 to 3 m (6 to 10 ft). The best-known species of the genus — A. excelsa, the Norfolk Island pine — is native to Norfolk Island where it grows to a large tree up to 60 m (200 ft) high with a pyramidal crown and needle-like leaves.

These trees are popular plants for the cold greenhouse as well as for home decoration. However, they require cool conditions in winter and therefore must be moved to a conservatory or other position where a temperature of 3 to 10°C (38 to 50°F) can be maintained. They must have ample air even in summer and should thus be placed by an open window. Unfortunately, cool homes are on the decline and besides, these plants do not tolerate the air pollution of cities so that, despite their beauty, they will probably soon stop being grown as house plants. The compost should be a mixture of leaf mould, loam, peat and sand, or John Innes potting compost. Propagation is by tip cuttings.

A. araucana, the hardy monkey puzzle from southern Chile, may be planted outdoors in a sheltered spot in the garden in warmer parts of Europe.

15. November 2011 by Dave Pinkney
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