Travellers along the Flinders Highway will know only too well how desolate the landscape is between Hughenden and Cloncurry. A tree is a rare treat, and even shrubs are hard to find. This desolation is not the result of wholesale clearing. In most areas it is natural grassland, dominated by Mitchell Grass (Astrebla spp.) and Flinders Grass (Iseilema spp.). A few sparse shrubs, such as Acacia farnesiana and Atalaya hemiglauca, are scattered throughout.
The grassland is there because conditions are very hostile for the growth of trees, and few species can cope with the conditions. The soil is a heavy clay which shrinks and swells according to moisture level, and is alkaline (with a pH of about 8). In addition, the rainfall is low (400-500 mm per year) and the shade temperature regularly exceeds 40°C in summer.
The small town of Richmond is a green oasis in the middle of this desolation. Exotic plantings are dominant at Richmond, with Bougainvillea featuring heavily. However, there is a healthy proportion of native plantings.
|Peltophorum pterocarpum (Yellow Poinciana)|
Peltophorum pterocarpum is undoubtedly the most commonly used native tree. It is planted on footpaths, in schoolyards and in backyards, and they appear to thrive. Their dense shady crowns must be highly sought after during the long hot summers. This species is widely cultivated in northern Australia, not only for its shady crown, but for the showy yellow flowers. It is said to be deciduous, but I have not observed this with cultivated specimens. It was originally named from Timor, and its natural occurrence in Australia is confined to the Top End of the Northern Territory.
|Hibiscus tiliaceus (Cotton Tree)|
Hibiscus tiliaceus is reasonably common at Richmond, and also forms a dense shady tree. Natural stands of H. tiliaceus are confined to the subtropical and tropical coasts, sometimes adjacent to mangroves; so it is obviously a very adaptable tree.
Surprisingly, there are several species of Western Australian eucalypts, including Eucalyptus erythrocorys (3 seen, moderately healthy), E. orbifolia (one very healthy specimen) and a 2-metre high specimen of E. kruseana at the Police Station.
Several other eucalypts are used: E. camaldulensis is common and does very well. E. coolabah is less common, but does equally well. These two species are indigenous to the Flinders River, just outside the town. E. torelliana is found on nearly every street and seems happy enough, although the crowns are often rather sparse. Other eucalypts present are E. shirleyi, E. argophloia, E. citriodora and a lovely specimen of E. ochrophloia next to the Guides hut.
|Eucalyptus shirleyi (Shirley's Silver-leaf Ironbark)|
Several forms of Callistemon have been planted, some of which are very chlorotic. Melaleuca appear to thrive: Melaleuca fluviatilis (formerly M. nervosa f. pendulina), M. linariifolia and M. bracteata were all observed.
Species only sporadically used include Owenia acidula, Acacia tephrina, Ficus obliqua, Terminalia catappa, Casuarina cristata, Vitex trifolia, Pleiogynium timorense and Brachychiton australis. The local species, Acacia victoriae and Atalaya hemiglauca have been planted occasionally to good effect.
Top |Home | You & SGAP | Getting Involved with SGAP | SGAP Qld Region | SGAP Publications
Local Branches | Study Groups | Study Group List | Queensland Nurseries | Special Articles