Top Australian Trees: #1 The Temperate Southern StatesBy Ian Maxwell (GranvilleSouth)
July 11, 2013
|Tasmanian Blue Gum|
Australia is home to thousands of endemic tree species spread over a diverse range of climates. Many are ideal for garden & park situations, others would suit collectors. This series will showcase a small selection of these species, starting in the cool, southern regions of the continent. Future articles will profile tropical Queensland, the country's arid interior & finally, the huge & isolated west coast.
The menu will take readers directly to each tree. Clicking the compass icons will return readers to the menu. There are lists of further information for each species, including suppliers, videos & botanical societies. The thumbnail photograph features a pair of kookaburras perched in a Tasmanian Blue Gum. Thanks goes to Robert Coghlan from the Australian Plants Society - Tasmania Inc. for taking & providing this picture.
Huon Pine (Lagarostrobos franklinii)
Our journey commences in rugged south-western Tasmania, where subtemperate rainforests have ruled since the Pliestocene. This is one of the last surviving true wildernesses with regions remaining untracked - even by aborigines - since rising seas seperated the island more than 11 000 years ago. Though officially considered extinct, the Thylacine or Tasmanian Tiger is thought by some to survive somewhere in the inaccessible wilderness of the south-west. This marsupial is one example of the ancient mystery that surrounds the region & another is the legendary Huon Pine.
Descending from distant ages, the Huon is second only to America's Bristle-cone pine in longevity. Individual trees have been dated back more than 3000 years & though merely rising an average one millimetre per annum, twenty metre Huons are not uncommon & forty metre specimens are not unknown. One of the most remarkable is an isolated stand of clones on Mt Read that has survived by vegetively propagating itself for more than 10 000 years. 
In its plegmatic growth & incredible longevity, the Huon is remnant of forgotten aeons of ecological stability. In the modern context, it is left at a standstill & is completely unrenewable. Nonetheless, for many years Huon Pines were logged intensively for their practically imperishable timber. The remarkable durability of Houn Pine is due to the presence of an essential oil evolved to protect the tree over the great expanse of it's life. This oil gives the lumber a unique odour & makes it ideal for ship-building, as it resists both rot & attack by marine organisms.
Thankfully, the species is now strongly protected by laws that allow only the collection of naturally fallen timber. As a results, a small industry remains in handworked products. The tree is available to the public as seed & enjoys a good reputation as a container tree. Vegetively propagated specimens can be seen at the Royal Botanic gardens in Hobart. Of course, growing Huon Pine will always be a long-term project that will likely be passed-on to your children.
Find Out More:
- DG Plant Files - Huon Pine
- Huon Pine Fact Sheet
- The Mt Read Huon Pine
- The Oldest Tasmanian (feat. video)
- Wildseed Tasmania
Tasmanian Blue Gum (Eucalyptus globulus)
Another beautiful Tasmanian tree is the state's floral emblem Eucalyptus globulus, the Tasmanian Blue Gum. This tree ranges naturally throughout the south & east of Tasmania as well as southern Victoria. Reaching a height of 70m in the wild, it is characterised by its thick, peeling bark that hangs in strips from the upper-trunk & branches. Beneath, the tree is smooth & pale. Like other blue gums, E. globulus gains its common name from its juvenile leaves.
The Tasmanian Blue Gum is a useful & widely cultivated species. Amongst other blue gums, it represents the majority of timber harvested in Australia. This hardwood is normally grown in plantations & used for light & heavy construction, maunfacturing rail sleepers & many other purposes. Blue Gums are also a major source of fragrant Eucalyptus Oil, which has a broad range of uses. Additionally, the Tasmanian Blue Gum's attractive flower is one of the largest amongst Eucalypts, serves excellently in fresh & dried floral arrangements & can be given to bees for a delicious, uniquely-flavoured honey. 
E. globulus is clay tolerant & likes wet conditions, but is sensitive to heavy frost. Whilst being suited to many subtemperate regions (USDA Zone 9), the size & relatively fast-growing nature of this tree make it better for parks than most gardens. For the same reasons, it can be trained into an excellent bonsai with its attractive bark, characteristic eucalyptus scent, creamy-white flower & colourful juvenile leaves. Like many other gums, these trees perform an important natural role as a canopy tree meaning they serve well as an avenue tree or wind-break in rural situations. They have been widely grown in the United States & are considered invasive in some areas.
A sub-species of the Tasmanian Blue Gum is E. globulus ssp. bicostata, the Southern or Victorian Blue Gum. It is more frost tolerant & ranging naturally across Victoria & southern New South Wales, is adapted to marginally drier & warmer climates. A cultivar that may interest more gardeners however, is E. globulus var. compacta, the Dwarf Blue Gum. This tree offers the obvious advantage of a smaller stature (up to 10m), but maintains the low maintenance & clay-tolerant characteristics of the species.
Find Out More:
- DG Plant Files - Tasmanian Blue Gum
- Association of Societies for Growing Australian Plants
- Floral Emblems of Australia
- USDA Weed Information
- Windmill Outback Nursery - USA
- Eucalyptus globulus ssp. bicostata
Grass Tree (Xanthorrhoea sp.)
Xanthorrhoea, the Grass Tree family is a group of uniquely Australian trees which would suit many collectors & any xeriscaper. This genus features 28 species appearing in Tasmania, across southern Victoria & New South Wales, South Australia & south Western Australia. Amongst the many species, only some such as X. australis, the Austral Grass Tree & X. quadrangulata, grow trunks above ground & take the form of a convential tree. Others develop extensively beneath the soil & appear as coarse hummocks. There is much more to these trees however, than first meets the eye.
Grass trees withstand drought but are hardy down to USDA Zone 9. They are extremely slow growing, live hundreds of years & regrow after bushfire. Fire can actually encourage flowering which occurs on spikes that grow up to two metres.
Though Xanthorrhoeas only grow around a metre each century, their flower spikes comparatively rocket skywards at one or two centimetres per day. They can flower two or three times each year & in the wild, spikes rising from charred Grass Tree stumps are often the first signs of life to return from bushfire. These spikes were used by indigenous Australians as spear shafts & fire-making drills. The young leaves were eaten along with the soft roots. The tough mature leaves were used as cutting implements. 
Xanthorrhoea have their own beauty for which it easy to acquire a taste. They are popular in Australian gardens, but can prove fairly costly to buy. They like well drained soil, full sun & make a great feature plant, especially in native gardens & xeriscapes. They have an unusual root system surrounded by microbes called mycorrhiza. When transplanting a grass tree, it is important to retain as much of its own soil as possible. Some gardeners recommend feeding newly planted Xanthorrhoeas with a cup of brown sugar in a bucket of water once each month for the first two years. The sugar is said to feed the plant's mycorrhiza & help it get established.
Grass Trees can live 600 or more years & most available in nurseries are transplants made available by land-clearing. No xanthorrhoea species is currently considered threatened, but they are unrenewable, protected by law in the wild & difficult to relocate. One should under no circumstance, attempt to take a Grass Tree from the bush.
Find Out More:
- DG Plant Files - Austral Grass Tree
- Park Victoria Fact File
- Monica Pawlan's Xanthorrhoea Information Page
- Windmill Outback Nursery - USA
- Aboriginal Uses of Native Plants
Snow Gum (Eucalyptus pauciflora)
The Australian Alps or Snowy Mountains rise from the cool forests of eastern Victoria & march northward into New South Wales. They are the continent's highest range, featuring a number of ski resorts, two National Parks & a unique subalpine ecology. One of the many tree species at home in the cool conditions here is Eucalyptus pauciflora, the beautiful Snow Gum.
E. pauciflora is also known as the Cabbage Gum, White Sallee & Weeping Gum. This species can be found over extensive areas of Victoria & southern New South Wales. Reaching around twenty metres, these are small to medium trees featuring elongated silver leaves & smooth, pale bark. Those at home on frigid mountain slopes, often grow partially prostrate with twisted trunks & stark, stretching branches. The bark on mature trees can become variegated & feature broad golden streaks. The flowers in summer, are profuse & snowy white.
Comfortable buried under snow & exposed to blasting winds, the Snow Gum would suit gardeners seeking a tree hardy in subtemperate areas (USDA Zone 8). The versatility of this species however, also means options for gardeners in warmer locations. Away from snowy highlands, E. pauciflora has adapted to drier, less fertile conditions. From such lowland populations, cultivars like "Little Snowman" have been chosen for propogation in temperate regions. 
The Snow Gum's botanical name pauciflora - meaning that it sparsely flowers - is a historical misnomer. Like most gums, E. pauciflora flowers heavily over the summer months, putting on an eye-catching & beautifully fragrant display. This tree is featured in many collections around the world & is available to the public in many countries.
Find Out More:
- DG Plant Files - Eucalyptus pauciflora
- Australian National Botanic Gardens
- Metro Trees - Little Snowman
- Windmill Outback Nursery - USA
Wollemi Pine (Wollemia nobilis)
Whilst the Snowy Mountains include Australia's highest peaks, The Great Dividing Range is its longest mountain chain. Extending for more than 3500 kilometres from Victoria, through New South Wales & up into northern Queensland, these mountains carry a number of local names. West of Sydney, they are known as the Blue Mountains because of the eucalyptus haze that surrounds them. Here this ancient plateau has been heavily eroded into valleys, ridges & canyons, some of which are yet to be fully explored. Testimony to this fact was the discovery in 1994, of the Wollemi Pine.
Wollemi nobilis is a member of the ancient Araucariaceae family, which includes other pines such as the Norfolk Island, Bunya & Monkey Puzzle. With a 200 million year ancestry, it is one of the oldest surviving trees on Earth. Represented by less than 100 mature specimens in the wild, it is also one of the rarest. Prior to its discovery by a bushwalker, the Wollemi Pine was thought to be extinct for up to two million years. The find led to an intensive recovery effort that finally saw the tree released to the public in 2006. 
Even compared to venerable relatives such the Norfolk Island Pine, the Wollemi is uniquely formed. Its fern-like foliage & unusual drooping cones make it instantly recogniseable. It is a fast growing tree with a proven record of beating the odds. Since coming into cultivation, W. nobilis has displayed an amazing tolerance to diverse conditions. It can be grown in full sun to semi-shade, in the ground or a container & in a wide range of climates. According to the WollemiPine.com ...
"The Wollemi Pine in Australia has grown in a range of temperatures from -5 °C to 45 °C (23 °F to 113 °F) & it could even be hardier than this. Trials in the USA & Japan have indicated that it will survive temperatures as cold as -12°C (10.4 °F)."
W. nobilis can be grown indoors so long as it enjoys a sunny position & will tolerate air-conditioning. It is available to gardeners in the United Kingdom, United States, Canada, Europe & Japan.
Find Out More:
- DG Plant Files - Wollemi Pine
- Botanic Gardens Trust
- Katalyst TV program (feat. video)
- The Dinosaur Tree
- Gardening Australia Fact Sheet