Botany

An Overview of the Australian Species of the Genus Pittosporum



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Members of the pittosporum genus are found in Africa, southern and eastern Asia, New Zealand and the Pacific Islands and Australia.

The foliage is usually glossy. The small 5 petalled flowers are cup-shaped or reflexed and may appear as solitary flowers or in clusters. Some have a pleasant fragrance. The seeds are contained in capsules which have a sticky coating. Depending on the species, pittosporums may be suitable as shelter plants, for pruning into a hedge or for growing in containers.

Around 20 pittosporum species are endemic to Australia.

One of this is Pittosporum undulatum, also known as sweet pittosporum, Australian daphne or Victorian box . It is found in all states bar Western Australia and the Northern Territory. It grows to 12 metres with a spread of 6 metres. It is a vigorous grower, bushy with shiny dark green leaves. The leaves are oval in shape with a wavy edge. Fragrant cream-white flowers are produced in terminal clusters from September to November. The flowers are followed by globular orange-brown fruits with sticky seeds. It is suited to open or shaded situations and adapts to a wide range of conditions. In some areas it has become a pest through its habit of forming dense thickets through self-seeding. It has some tolerance to exposed coastal situations and will survive light frosts.

The banyalla (Pittosporum bicolour) is native to Tasmania and cool wet parts of south-eastern Australia. It is a small tree or erect bushy shrub. The leaves are lance- or oval-shaped, have a leathery texture and are dark green in colour and felted underneath. The small, fragrant flowers, which appear in spring, are yellow with dark red markings. The seed capsules are a greyish colour.

As a contrast, Pittosporum lancifolium (native orange or orange thorn) comes from northern New South Wales and southern Queensland. It has stiff spiny branches with leaves to 5cm long. The leaves are lance-shaped, green and shiny. The greenish flowers appear in spring and are followed by orange berries.

The rusty pittosporum (Pittosporum ferrugineum) has rusty brown hairs on the undersides of leaves and on young growth. It is found in northern Australia and in south-east Asia. The leaves are lance-shaped or oblong. Fragrant creamy yellow flowers are produced in terminal clusters in autumn and winter. The fruiting capsules are yellow.

Pittosporum phylliraeoides or butterbush is synonymous for Melia azedarach var.australasica. It is an upright small tree often found in extremely arid conditions. It has pendulous branches and yellow open-petalled fragrant flowers from September to November. These are followed by decorative yellow fruits. It is frost resistant.

Most species will grow in sun or part-shade. They like well-drained soil. In cooler climates they may need the protection of a sunny wall, conservatory or greenhouse. Regular pruning will help retain the dense foliage.

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