As conditions get hotter and drier, not just over summer but year round, gardeners are seeking shade for both the house and the garden. Trees not only give shade, they also make areas cooler, create habitat and provide food for creatures of all sorts, give much-needed privacy and filter out unwanted views. Every garden needs at least one tree, and for those who want a tree in a hurry, it’s time to plant a fast-growing Australian native tree. A fast-growing tree should reach a generous height in around five to seven years from planting.
When people think of fast-growing Australian native trees, it’s usually gum trees that spring to mind - however, many species of gum are far too big for a suburban garden. The good news is that plant breeders have developed dwarf varieties with all the benefit of a large gum tree (including fast growth and shade) without turning into forest giants.
One of the most elegant of all the gums is the lemon-scented gum (Corymbia citriodora) but it grows into a very big tree 30m or more in height. With the lemon scent and slender white trunk of the forest giant, dwarf lemon-scented gum ‘Scentuous’ reaches just 7m high and 5m wide. It has white flowers in summer and colourful pink stems. For a small gum with show-stopping colour, grafted red flowering gums such as C. ficifolia ‘Summer Beauty’ (pink flowers) and ‘Summer Red’ (red flowers) are garden-friendly at just 6m high and 3m wide. They flower in summer.
Moving away from gums, the blueberry ash (Elaeocarpus reticulatus) is one of the best fast-growing garden trees as it is evergreen, narrow and quick off the mark. This prettily named tree comes from the rainforest and does indeed have blue berries. They’ll never take over the blueberry market, but as far as birds are concerned, they’re delicious. The blue berries follow the tree’s dainty white or pink flowers, which have fringed petals. This tree is an ideal choice for a tall screen planting in sun or shade. When closely planted they’ll grow about 3m wide and can eventually reach 10m-15m high. The pink-flowered form is called ‘Luscious’.
Also from the rainforest is water gum (Tristaniopsis laurina), a dense tree with bright green leaves and clusters of small yellow flowers in summer. It grows in naturally moist areas beside streams so it benefits from regular water after planting. It will reach 5m to 15m high depending on growing conditions.
Where there’s plenty of room for a spreading tree, the lemon-scented myrtle (Backhousia citriodora) offers shade and shelter along with fragrant, lemon-scented leaves. It grows to around 8m high and 4m wide in gardens and, in summer, is laden clusters of white flower. As this is a subtropical rainforest tree from the east coast of Queensland, it needs a little frost protection when young and also benefits from regular watering until it is well established.
For a smaller flowering tree, select a tall shrub that can be trained into a tree shape. Tall grevilleas such as ‘Moonlight’ (white flowers) ‘Sandra Gordon’ (yellow) and ‘Honey Gem’ (golden orange) can be grown as small slender trees. Simply select a plant with a single stem and remove the lower growing branches as the tree grows. These varieties may reach 3m-8m high and 2m-5m wide. Closely planted to they provide privacy and dappled shade. The birds and insects will love these nectar-rich flowers adding to the delight of having a tree in your garden..
For a denser but equally fast-growing tree or screen, native frangipani (Hymenosporum flavum) is a great shrubby tree 6-8m high and 5-6m wide. For a shade tree, select a specimen with a single trunk and remove lower growing branches as the tree grows. For a tall screen simply prune it into a columnar shape. As well as shiny green leaves, native frangipanis have clusters of creamy yellow flowers with a heavy fragrance. This tree can grow in sun or shade but produces its best growth with a little shelter from hot afternoon sun, good soil and regular water.