When it comes to screening off a property for privacy or security reasons, a row of dense, screening evergreen trees is a greener and more attractive choice than throwing up walls or artificial security screens. However, choosing the right species of tree for an effective screen involves more than just looking for the biggest, meanest looking tree you can find -- effective screen trees should have dense, even foliage, and should be able to grow in closely planted rows without crowding or competition.
Luckily, you don't need to look far to find trees eminently suited to these purposes, as Australia's native ecosystem offers up a variety of robust, easily-cultivated evergreens ideally suited to screening purposes. Below are three of the best varieties, along with their particular strengths and weaknesses:
Lilly pilly (Syzygium smithii)
Also known as the 'monkey apple' in New Zealand, these small evergreens are often planted together while young and pruned to form tall, hedge-like screens. Lilly pilly has dense, vibrantly green foliage that grows evenly along the entire length of the trunk, providing thorough screening that can also be rather attractive. This is especially true in autumn and winter, when the tree bears small white flowers and colourful berries. These trees can tolerate drought and various amounts of shade, and are resistant to the predations of parasitic psyllids. They are also fire retardant.
Lilly pilly should, however, always be well established before planting, as young trees are vulnerable to lack of water, and can quickly lose foliage to dehydration. These trees are also relatively vulnerable to high winds if planted in exposed areas, with young plants becoming quickly becoming bowed and stunted if left to the mercy of the elements.
Queensland tree waratah (Alloxylon flammeum)
Also known as the red silky oak, this native evergreen is the ideal choice for anyone looking to make a statement with their screen. These rainforest trees sprout leaves along the lengths of their long, slender branches, providing consistent cover. The real appeal of these trees, however, is their magnificent flowers, which grow in large, vibrant red clusters throughout the spring. These flowers tend to attract nectar feeding birds such as hummingbirds, adding to their aesthetic appeal.
However, such beauty always comes at a price, and Queensland tree waratahs are more difficult to care for than other screen evergreens. Waratahs require well drained soil and fun sunlight to remain in good health, and without occasional applications of mulch and fertilisers, as well as frequent watering in summer, these trees will start to die off. You may want to have your soil tested before you commit to planting a full screen, as excessive levels of phosphorous in the soil will stunt and damage new growth.
Ivory curl (Buckinghamia celsissima)
Why screen with leaves when you can screen with flowers? The ivory curl is another excellent choice for an attractive screen, as its flowers grow in large, vibrant white clusters and droop over the leaves and foliage to provide an effective privacy screen for much of the year. While ivory curl trees can grow to a towering 25m, cultivated varieties are generally much smaller, so you have a range of options when it comes to the size of your screen.
However, you may not have as much control over the size of your ivory curl screen as you'd like, as the ivory curl is more vulnerable to temperature variance than some other native evergreens. The plant is particularly vulnerable to cold and nighttime frosts, making is unsuitable for colder regions of the south, and will have similar trouble surviving in waterlogged soil.
If you're looking to buy trees for your home, visit a nursery like Din San Nursery.