Brachychiton rupestris

bottle tree

 

Brachychiton rupestris

(T.Mitch. ex Lindl.) K.Schum. 1890

pronounced: brak-ee-KY-ton roo-PEST-riss

(Malvaceae — the hibiscus family)

 

common name: bottle tree

native 4Brachychiton is from the Greek βραχυς (brachus), short and χιτων (chiton), a tunic. This refers to the coating on the seeds. Rupestris is from the Latin rupes, a rock – growing near or on rocks.

This tree, when it is mature enough to develop its typical shape, does indeed look like a bottle.The photographs  taken of the same tree over a period of years, show the development of the trunk. The bottle shape of the trunk will usually begin to become apparent at between 5 and 8 years, but it can take up to 15 years. The swelling is due to the water held in its trunk, as insurance against hard times.

The tree is endemic to central Queensland and northern NSW. It is particularly prevalent in the western Queensland town of Roma, where not only are there some fine enormous old specimens, but also many of the streets are lined with bottle trees.

The trunk of a mature bottle tree can reach up to 2 m in diameter. The tree can grow to a height of 18–20 m, but is usually smaller in cultivation. The canopy spans 5–12 m. It grows in a soil that consists of a medium to heavy clay, silt, sand, and volcanic rocks; yet the tree is quite hardy and can tolerate a variety of climates and soil types.

It has been cultivated in southern Australia for many years, and can be seen as an ornamental feature in parks and gardens in many parts of the world. It can be propagated either from seed or from cuttings. It is important to wear gloves when collecting seeds, as they are covered with irritant hairs. The bottle tree transplants easily, even when quite a number of years old, and, no doubt due to its inbuilt water supply, can survive quite long periods, even up to 3 months, between being uprooted and re-planted.

The leaves are about 10 cm long, and vary greatly even upon the same tree. They may have entire margins, as is usual on old trees, or be deeply lobed (3–7 narrow lobes), particularly on young trees.

New foliage is an attractive pinkish colour. The leaves drop from the tree before it flowers. The canopy will also thin out during a drought.

The campanulate flowers are creamy white, with red stripes or flashes, and usually form between October and December, in clusters at the ends of the branches. They are not especially conspicuous, and are followed by woody boat-shaped seed capsules up to 3 cm long, containing many large seeds.

The tree does not get attacked by many pests, but damage to the trunk makes it susceptible to fungus infections. The larvae of the Kurrajong Bag Moth Dichocrosis clytusalis use it as a food plant.

The bottle tree not only is ornamental, and provides wind protection and shade, but also has been a food and water source to the aboriginal people in times of need. There is a significant amount of water stored between the inner bark and the trunk. Holes were carved into the soft bark to create reservoir-like structures. The seeds, roots, stems and bark have all traditionally been a source of food for people and animals alike. The seeds, however, must be roasted before eating. Use has also been made of the fibrous inner bark to make twine or rope, and woven together to make fishing nets.

 

Photographs taken in Picnic Bay 2010-2015 and Horseshoe Bay 2013
Page last updated 22nd October 2018