Say “bottle tree” to a diverse group of people, then take a poll of the images that come to mind. Chances are good that someone will mention trees near a crossroad, hung with blue, glass bottles, while someone else will mention the squat, gnarled trees of north western Australia and Madagascar, and a third might mention the graceful wine-bottle shaped trees of Queensland, Australia.
From this imaginary poll it is easy to see that when bandying about the term “bottle tree” it is a good idea to know what kind of tree you really have in mind. For purposes of this writing, we shall let the tree hung about with blue glass bottles inhabit the realm of folklore. Although interesting, it goes far afield from our main topic of interest.
“Bottle tree” can refer to any tree with a trunk that swells when water is drawn up into it. These trees are of plant type referred to as “vascular.” Vascular plants have vessels that draw up water, storing it for times of drought. They also have a separate type of vascular system that is used for photosynthesis. Bottle tree are often deciduous, dropping their leaves during the dry months to conserve water. Both are relatively hardy.
Australia supports two kinds of bottle trees: (adansonia gregorii) of western Australia, and the Queensland Bottle tree (brachychiton rupestris). Although they are both sometimes called bottle trees and share certain characteristics, they are in fact different species. Adansonia gregorii grows primarily in Kimberly, the north western part of Australia, while the Queensland Bottle Tree, brachychiton rupestris, can be found in Queensland. Other brachychitons, such as brachychiton australis can be found in other parts of Australia.
The Kimberly region bottle tree is often called “boab”, and is most closely related to the baobab tree in Africa, but no one is quite sure how it arrived on the island continent. There are eight types of baobab tree, most of grow in Madagascar. There are baobab trees in Africa, as well as the “boab” that grows in Australia.
There are several theories as to how or why the boab adansonia gregorii arrived in Australia. Some people think it might have been growing there when the continents began to drift apart. Some suggest that seeds drifted on the water, but others point out that the porous seeds of the boab would have become waterlogged. Still others suggest that it might have been transported by humans, connecting the trees with the Kimberly Region rock drawings. This idea is disputed by some, who say that the trees have been in the area since before humans.
Regardless of how they arrived, adansonia gregorii, or boab trees are important to the area. They, and their cousins in Africa, are an important source of food, fiber, and even shelter. Some of the trees are so large that they can be entered. Two boabs in Australia are called “prison trees” because they were used to sequester prisoners when traveling from one place to another. Unlike the Queensland bottle trees, the boabs have ungainly, bulbous bases that one writer described as “gouty” in appearance.
The baobabs from Africa have large white blossoms that open at night shortly before the rainy season. Observers report that the flowers open so quickly that you can see them unfurl. The fruits are used as food, and the leaves can be eaten as salad. Immature trees can be pulled and the roots eaten like carrots. The hard seed pods can be turned into artwork, and fibers from the bark can be used as rope, fishing lines, or weaving. In some areas the “boab” or baobab is called the tree of life because of all the good things that can be made from it.
Therefore, it should not come as any surprise that everybody wants a boab tree. But there are excellent reasons why this is not a good idea. The first is that baobab trees are believed to currently be suffering from global warming. Although these magnificent, and often strangely shaped, trees store water within their trunk, even they can be challenged by a lack of rainfall. This especially true during leafing and blooming season. Second, these trees grow sparsely and are sacred to various people. Third, they frequently do not thrive outside their native area. For example, an effort was made to grow boab around Sydney, and it was discovered that the weather was simply too cold.
Even the success story of the Gija Jumulu is qualified. In 2008, the Gija Jumulu needed to be moved because of the re-routing of a highway. This was a massive undertaking, involving earthmovers, a big truck and even reorganizing power lines, signs, and other things that could potential damage the giant tree on its way from the Kimberly area to King’s Park Botanic Gardens in Perth. In spite of some bark scarring en route, the giant tree lived, and as of 2018, was putting out new roots and new branches. Unfortunately, fruit has not been an option because of lack of native pollinators. This tree was so loved that the Gija people held a special smoke ceremony to wish it well on its journey and to keep the people transporting it from harm. At the other end, the Nyoongar people held a welcoming ceremony. Since then it has been carefully cared for by those who understand its needs.
So you see, having your own “jumulu” is truly not a good idea. It is a bit like owning a white elephant: highly prestigious, challenging, and more than a little expensive.
That does not mean that you cannot have a bottle tree. The Queensland bottle tree, originating in Queensland, Australia, is much more forgiving and a lot easier to grow. The young trees can be cultivated in containers. The older trees might be found in bottle tree thickets, areas where low growing brush and dense vines have grown up around one or more bottle trees. Brachychiton Rupestris, the Queensland Bottle tree, has been successfully transplanted and grown from seed. While it becomes a little confused about seasons when planted in the northern hemisphere, B. Rupestris has proven adaptable. Its graceful shape makes it a crowd pleaser as a feature tree, and it, too, has edible parts and stores water for the dry times.
If you are interested in owning a Queensland bottle tree, click here to learn more. Or you could just hang some blue bottles from a tree that stands near a crossroads.