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ABout Xanthorrhoea
Xanthorrhoea is an Australian native plant genus. Commonly called grass trees, Xanthorrhoea plants are also known as balga grass to the Australian aborigines, which is their word for black boy. The Aborigines probably called these plants balga because after a wild fire, the bottom leaves burn away revealing a singed black trunk with long green reed like leaves extending from the top of the trunk giving the appearance of child like black figures. The Xanthorrhoea australis in the photo to the right is from the Arsia web site and shows trunks.

Xanthorrhoea Quadrangulata The photo on the left is a Xanthorrhoea Quadrangulata from desert-tropicals.com that is probably about 8 - 10 years old. It can take many years to expose the trunk, and that happens on larger plants by manually cutting away the bottom leaves that have turned brown, as the result of a wildfire burning them away, or by the plant growing large enough to expose the trunk beneath the leaves.

All species of Xanthorrhoea are very slow growing, but they are also very long lived -- up to 600 years! Long straight spears of white blossoms extend from the top of the tree especially in the year following wild fires. A photo of a blooming spear of Xanthorrhoea Preisii from the Missouri Botanicals web site appears below to the right.

There are many Xanthorrhoea species and subspecies from all over Australia and Tasmania as listed and described below. Generally frost tolerant, all Xanthorrhoea require well-drained soil and a sunny location because they are prone to root rot. They can be grown very successfully in pots.

Australian Aborigines
Australian Aborigines collected the resin flakes from around the base of the stalk, heated them, and rolled the resulting substance into balls. The resin would later be reheated and used to glue stone flakes to wooden spear shafts or woomeras, and to join and repair various broken implements.

Aborigines lit fires by rubbing two pieces of the dry flower stalk together, soaked the flower spikes in water to make a sweet fresh or slightly fermented drink, and used the tough seed pods as knives to cut meat or harvest insect larvae from inside the old flower stalks and the dead bases.

European Settlers

European settlers harvested the resinous gum to make varnishes and lacquers. During World War II many cans of tinned food sent to the Australian troops in the Pacific had a protective coat of grass tree varnish to keep the containers from rusting.
Native Wildlife

The spikes are packed with strongly scented flowers and attract a wide variety of insect, bird, and mammal pollinators.

Sprouting & Growing

Xanthorrhoea australis sprout Xanthorrhoea take about seven years to mature. After maturation, the plant can bloom anytime, but seems to do so more prolifically after being singed in a grass fire or exposed to smoke. The seeds are contained in a capsule which splits to scatter the seeds and germinate readily when water is applied.

A botanist from The Arboretum of Los Angeles County explains how to gather the seeds, as follows: As soon as the birds show an interest in the stalks, gather them gently, cut them into lengths and put them into paper supermarket bags. Do not put them in plastic bags, they will mildew. Let them dry, and then beat on the bag with a broom stick. Take out the stocks and the seeds will be in the bottom of the bag.

If you want to leave the stalks on the plant - because they look really cool - just wait until the pods open on the stalk and the small black seed looks like it's getting ready to fall out. Use a small tweezers or your fingers to gently remove the seed (be careful not to damage it!). If you let the stock and open pods dry out over a few weeks, you can remove the pod with your fingers and then remove the seed from the pod. You can also shake the stalk and the seeds will tumble out. Have something below to catch the seeds. I found that cobwebs work really well for catching the seeds that fall.

Xanthorrhoea australis will sprout in regular potting soil. I use an organic one that comes from my local nursery. Place the seed about 1/8 to 1/4 inch below the surface and cover with a thin layer of sand (about 1/8 inch). The sand forms a permeable layer through which to water without disrupting the seed below. I've found that without the sand, it can be too easy for the seed to float to the top of the soil when I water, and then it does not sprout. Although, if you do it without sand, you can just push the seed deeper into the soil - up to an inch - and they still sprout.

It can take 6-7 weeks to see the first sprout, although I've seen some sprout in 2-1/2 weeks. The photo on the right is a brand new sprout. It is not unusual for the black seed to stay on the tip for a few days or weeks. It eventually drops off.

Xanthorrhoea australis sprout Growers from the Windmill Outback Nursery use 50% sand with 50% perlite and place the seed about 1/4 inch below the surface. With this method, once the seed sprouts it should be moved to potting soil with perlite (about 50% each) because it will need nutrition from the soil to grow. The photo on the right shows a sprout that has started to divide.

Another method I'm trying that I learned from the Australian Native Plants nursery is three parts Perlite to one part peat with a light covering of washed sand twice the thickness of the seed. Drench the seed with a fungicide after sowing to prevent "damping off."

Unsprouted seeds should be kept moist but not wet. Once they sprout, keep them moist but be careful not to over water. They grow very, very slowly and do well in containers. Once established, they can live 600 years.

To learn more, read these interesting and detailed notes from John Summerfield in Western Australia.

Species List

The Xanthorrhoea genus is part of the Xanthorrhoeaceae family, which is made up of small trees or perennials with woody stems. The leaves are tough and linear, and the flowers are radially symmetrical, bisexual, and look like spikes. The seeds are individually contained within capsules. The following is a list of known Xanthorrhoea species and subspecies with a brief description of some.

sumber : Monica site.com