Monday, July 19, 2010

Balga - Xanthorrhoea (Grass Tree)

From Balga
Monica's Site - most complete
Photos by P. Wilshaw and M. Taylor

Habitat - Throughout Australia, Tasmania

Balga is the aboriginal word for "Black Boy," a term that may be considered offensive to oversensitive white ears, but a term which obviously causes no consternation to our indigenous population. One aboriginal who was told that the term was offensive said "Well then what should I call it?" The term "Black Boy" probably arises from the appearance of the trunk which is exposed when fire burns away the old leaves and turns the trunk black.

Xanthorroea are very slow growing, very long lived plants. Not all species have trunks, but here in the park the X. preissii is the species that grows a trunk. It can take 10 years for the trunk to form from old leaf bases held together by resin. After that, it will be 75-100 years before the trunk is one meter tall. At the end of their life, at around 600 years they may approach 20 ft high.
In many websites you may see that there are 8 species of Xanthorrhoea, but Monica's Site lists a startling 32 species, all native to Australia, but they can be grown in similar climates world-wide with care.

Because they are so slow growing, transplanting grass trees has become an important part of preserving the ones that are removed from mine sites and residential clearings. We have several transplanted balgas in the park that you may have noticed around the new location of the bus stop. They can also be grown from seed as discussed at Monica's Site.

From Balg
Aboriginals used the plant for so many things that one of our guides refers to the grass tree as the "One Stop Shop." We all know that the grass tree exudes a dark red resin when the trunk is heated by fire. That resin was collected, heated and formed into balls for later use when it was re-heated and mixed with charcoal and kangaroo dung to make an epoxy like material to attach sharp stones to sticks making knives, hatchets and the like and to repair broken implements. This same resin was harvested by early European settlers to make varnishes and lacquers. Cans of tinned food were protected with a coating of this lacquer during WWII. The flower stalks are light weight and airy which made them ideal for fire-making by rubbing together. The flowering seed stalks are rich in nectar so they were soaked in water to make a sweet drink. If allowed to sit, this sweet drink would ferment making a slightly alcoholic drink. The seed pods are very tough and were used as a knife to cut meat. Young leaf stalks are a tasty vegetable, and the edible Bardie Grub lives in the crown of the plant. And the dead leaves, if not burned away by fire were be used as thatch and as tender for fire making.
Leaf Cross Sections Balga

In the park, we are limited to only two species, Xanthorrhoea preissii and X. brunonis. X. preissii is the "common grasstree." It grows a tall trunk and has a diamond shaped cross section in the leaf. The grasstree at the Tuart Lawn entrance to the Banksia Garden is a X. preissii and is about 200 years old. X. brunonis grows close to the ground with no trunk, has a narrow seed stalk better for using as fire sticks and a triangular cross section to the leaf.

The seed stalk, regardless of the species can grow at a rate of 2-3 cm per day and can reach lengths of 3 meters. The stalk is packed with nectar and attracts a wide variety of insect, bird and mammal polinators. P. Wilshaw got a picture of bees and a wattyl bird working the same two stalks in the park. He also got a picture of a bee flying into a seed stalk upside down. Maybe that nectar can ferment on its own? Click on any of the pictures to the right to be taken directly to the Balga section of the KPGuides photo album.

M. Taylor

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