Purchasing ornamental trees for planting in urban areas can often be a surprisingly challenging affair, particularly for Australian customers -- the considerable air pollution present in many Australian cities and population centres, combined with the country's notoriously harsh climate and inconsistent soil quality, can make it very hard to find a species of ornamental tree capable of standing up to such punishment.
However, the solution to such problems could be lying right on your doorstep. Australia's unforgiving ecosystem breeds hardy trees, and many of them are more than durable enough to thrive in busy urban areas. The natural isolation caused by Australia's island location also makes for some unique and eye-catching trees and blossoms. The following species of tree are tough, attractive, and suitably compact for urban planting.
Queensland bottle tree (Brachychiton rupestris)
While botany tends to be full of deceptive names, the Queensland bottle trees is exactly what it sounds like -- it hails from Queensland, and has a distinctively bulbous, bottle shaped trunk. They have a wide range of properties well suited to urban cultivation; they are resistant to pollution, can survive in dry soil and prolonged droughts, and thrive in full sun exposure. They also have weak, non-invasive roots that are unlikely to interfere with foundations, pipes etc. These trees are also fine aesthetic choices, producing delicate, cream coloured blossoms throughout the autumn.
However, while Queensland bottle trees require very little maintenance and care, they cannot be left alone entirely. While bottle trees can be grown indoors, even in bonsai forms, wild specimens can reach up to 20m in height. As such, they will require frequent pruning and crown reduction to keep them at a manageable size, while some owners may choose to have theirs pollarded to limit growth.
Blunt-leaved tulipwood (Harpullia hillii)
These slender deciduous trees, which are native to eastern Australia, are often seen providing shade on streets and in parks, and their thick, sprawling canopies are ideal for providing some much needed relief from summer sun in public areas. Despite their stately and somewhat fragile appearance, these trees are enviably tough, able to tolerate air pollution and poor soil. They can also thrive in partially shaded areas, making them a good choice for areas hemmed in by tall buildings or other obstructions. White blossoms in spring are followed by vibrant orange seed pods in autumn.
While most blunt-leaved tulipwoods peak before reaching 10m in height, some can reach as high as 20m, so some maintenance and trimming may be required if your trees are unusually large. You should also be prepared for heavy seed dropping in late autumn, as the fallen seed pods can turn into a sticky and unsightly mess underfoot.
Wild quince (Alectryon subcinereus)
Also known as the native quince, this compact tree is an excellent choice for cultivation in areas with limited headroom, particularly underneath power and telegraph lines. The tree has a maximum height of 10m, and is slow-growing enough to require minimal pruning. Particularly small specimens are practically shrubs, and make for an excellent and unusual alternative to standard boundary hedges. Wild quinces also like to show off, with their copper-coloured young leaves and small fruits which attract many attractive birds. These trees are tolerant of heavy pollution, are drought resistant, and can grow in both full sun and partial shade.
The one key disadvantage of wild quinces, however, is that the fruits that attract birds also attract some more unsavoury wildlife, such as wasps, mosquitoes and other stinging insects. Potted quinces can easily become breeding grounds for insect larvae without due care and attention, and may be unsuitable for enclosed areas.