 Bronzewing pigeouns feed on fallen wattle seeds. Recapping the benefits of planting locals Indigenous plants are well adapted to the unique climate and soil of their local environment. The local insects, birds, and marsupials know and rely on the food and shelter that these very specialised plants provide. Imagine that a new supermarket chain has bought out your familiar corner store, and now it sells only brands you've never heard of and there's worse, the new supermarket only opens at inconvenient times. In the same way, local wildlife have evolved with the local plants and know their cycles, they know what the nectar/pollen tastes like and when it becomes available. They know where to find insects under the bark and which bark to use to build nests. Some wildlife may adapt quite well to the new plants in our gardens, but they may not be as healthy as they would be feeding on the indigenous plants that they have evolved with for millennia.  Blue tongue skinks need a sheltered ground layer Why plant wattles Wattles are important plants in most ecosystems because of the benefits they bring to other plants and to local wildlife. In nature, it’s common to see four or more wattle species in a wild ecosystem, ranging from the taller understorey plants down to the bushy shrub-layer wattles that I’d like to talk about today. Many of the shrub-sized wattles that are found in the Geelong region are rarely planted in gardens, yet they are a real asset in urban ecosystems. Not only are wattles an important source of food for wildlife, but they also add plant diversity, restore nitrogen to garden soils, add vibrant colour when they flower, and they’re quick growing, which makes a young garden look more grown-up. They are also quite long-living (15-20 years) and very competitive Planting small wattles under tall/mature trees The competitive nature of wattles is legendary. Many species of wattle evolved as pioneer plants that pave the way for other vegetation that needs shelter. They also compete well with existing trees. Two small bushy wattles that will fill in bare spaces and provide the very important shrub layer under mature trees are the delightful spring-flowering Gold-dust Wattle, A. acinaceae; which grows to 1 m tall, and the Myrtle Wattle, A. myrtifolia; with its distinctive red branching and red stems. It will reach a height of 2 meters. The Myrtle Wattle will brighten up the garden in mid-winter with its bright yellow pompom flower clusters. Getting plants started in dry areas under mature trees:
The benefits of providing a bushy habitat Their bushy form is very important if you want to attract small birds. If you want to bring Superb Fairy Wrens into your garden within the first few years of planting, include a tight clump of bushy wattles. For example, in the same space that you might plant a shrubby grevillea, plant three bushy wattles. Their interlocking branches will provide important protection from the neighbours’ cat that’s out prowling at night. If you want to provide super-safe accommodation for small birds, choose prickly wattles like the Hedge Wattle, A. paradoxa; or Prickly Moses, A. verticillata. The Hedge Wattle has superb bright yellow pompom flowers in spring that will brighten up any dark corner in the garden. Its extraordinary beauty is the paradox as it contrasts with the sharp cat-deterring spines along its branches and stems. A line of these shrubs planted 2 m apart will turn heads, and not just the fairy-wrens, when they’re in flower. I was interested to learn from Dr. John Morgan from Latrobe University that the common taller form of Hedge Wattle was introduced into Victoria from Kangaroo Island in the early 1900s to create stock-proof hedges. The form that is indigenous to Victoria is smaller (1-2 m) and less invasive. Prickly Moses is often found on waterways and will tolerate damper soil conditions than the Hedge Wattle. It can grow up to 4 m and its large pompom flowers from winter to spring are a refreshing pale yellow. The prickly part of this bush is its dark green leaves that taper to a point. Tough and sweet-smelling Some botanical names focus on an important feature of a plant that helps with its identification. For example, a beautiful shrubby wattle that is found throughout southern Victoria, as well as along the east coast, is the Sweet-scented Wattle, A. suaveolens which is the Latin word for sweet-smelling. This bushy sprawling wattle will grow to a height of 2 m and has delightful honey-scented creamy flower heads from June, continuing through the winter. It's one of the earliest wattles to flower. Like the smaller shrub wattles that compete well, the Sweet-scented Wattle will do the hard work under mature trees, fill up those empty spaces, and provide very useful wind shelter. Like all hardy plants that are planted in dry competitive environments, the Sweet-scented Wattle will need a little more effort to plant as described earlier, but the extra time spent will be well rewarded. Taller shrub wattles that will also perform well in these tough conditions are the Hop Wattle, A. stricta and the Varnish Wattle, A. verniciflua. Both will grow to around 3 m tall and both will provide robust shelter in windy, exposed positions. Both the Hop Wattle and the Varnish Wattle will also make a statement as single specimens in a small garden or as a natural-looking clump planted for wind shelter under mature trees. Both flower in spring, providing a welcome splash of refreshing yellow in the garden or plantation. The varnish wattle has particularly attractive small glossy leaves that give it a year-round appeal to gardeners. Food plants Two small bushy wattles that literally bring to the table something special are the Wirilda/Swamp Wattle, A retinodes; and the Coast Wattle, A. sophorae. Both are grown commercially for their edible seeds that are roasted and used for nutty food flavouring and a coffee additive. Click here to read about a commercial grower near Port Fairy. Both wattles will grow in tough garden environments and are well adapted to front-line coastal planting. Though, be cautious if you are planting A. sophorae because it is known for its 'weediness' along coastal fringes where it can spread and take over, smothering smaller indigenous plants. Both species display vivid yellow pompom flowers in spring.  Thin-leaf Wattle, providing the ground layer under Ironbarks. Photo: Castlemaine Flora To make up the ten small wattles I have included a beautiful tough ground cover wattle from west of Geelong, The Thin-leaf Wattle, A. aculeatissima. This is an attractive, extremely hardy plant for rockeries or hot, exposed dry garden beds. This beautiful wattle will provide important shelter and a safe haven for skinks like the iconic Blue-tongue, as well as small birds. Its narrow leaves are a little prickly because of their pointed tip, which makes them an important habitat plant for all the small ground-living fauna that we want to attract to our gardens.  A quick tip prune will keep the wattles looking fresh, and it also improves flowering. Maintenance To keep small wattles looking fresh and attractive, chop them back every year or two after flowering, (or the following autumn if you plan to collect seed), with the hedge trimmers, by cutting the growing tips. This process of tip pruning not only makes the wattles bushier by increasing lateral growth, but also encourages them to flower more prolifically. Your clippings can be allowed to fall onto the garden bed as a woody mulch to suppress weeds. For prickly wattles, slide a tarpaulin under the plant before clipping to remove the thorny clippings that will make hand weeding unpleasant. These prickly clippings can be laid around tender shrubs to protect them from rabbits and hares. Avoid pruning wattles too hard, as it can cause them to die back. A rule of thumb is to avoid cutting stems that are larger than pencil thickness.  Transplanting wattle seedlings with a single shoot is quick and easy. Propagation Acacias are easily propagated from seed. To read more about this process and how to inoculate young plants to improve their health and vigour click here.  Next month.
Mycorrhizal fungi – the missing link in revegetation
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Acacia implexa Pale yellow pompom flowers on a Lightwood About thirty years ago, I set off to collect my first Lightwood seed on a roadside near Lethbridge. I had been tipped-off by a local farmer, who said that it grew alongside a shrubby form of Blackwood. I remember driving up and down the gravel road several times, wondering if I had been sent on a wild goose chase. The trees on the roadside all looked like Blackwoods through my open window. At this stage of my nursery career, I had only read about Lightwood and didn’t know about the subtle features that distinguished it from it's very close relative, Blackwood. Though, a walk amongst the roadside trees soon revealed that there were indeed two different species growing side by side. With a more experienced eye, I can now comfortably identify Lightwoods while driving along a country road or highway, and it has become one of my favourite medium-sized wattles. Commonly pronounced – im-plex-a (no surprises there) Its species name, ‘implexa’ hints at another distinguishing feature of the tree. Its spiralling seed pods form tangled clumps and look very like untidy bird’s nests hanging from the branches. Implexus is Latin for tangled.  Where does it grow? & what does it look like? The Lightwood is well suited to the soils and rainfall of the Geelong region. It can also be found growing on the basalt plains west of Geelong on stony barriers, in the eastern parts of Victoria, NSW and southern Queensland where the rainfall above 450 mm. In areas with high rainfall like the Otway Ranges, it’s unlikely to be seen, but this is where Blackwood’s excel and grow into forest giants. The Lightwood is an attractive, hardy, drought, frost-tolerant, upright small tree that grows 5-10 m tall. Though very like the Blackwood, its leaves are greener and distinctly sickle shaped.  Another important difference between Lightwood and Blackwood is the seed. The glossy black seed of the Lightwood has a small bone coloured aril (the aril connects the seed to the pod) at the end of the seed, whereas the Blackwood has a large orange aril that surrounds the whole seed. The Lightwood has a rough bark and an attractive grey trunk. (click on the image to enlarge)  A Four month old Lightwood grown from seed and ready to plant The Lightwood is quite long-lived, thriving for 30 – 50 years. It still can be found on roadsides and on stony barriers, though it is becoming rarer. It’s more adaptable than the Blackwood and does well in dry, windy, exposed locations. The Lightwood is suited to all well drained soils. It's a fast-growing tree and will commonly reach two meters tall in the first twelve months after planting. The Lightwood is therefore very useful for erosion control, and its potential to sucker when its roots are disturbed is another benefit in eroded landscapes. Its tendency to sucker makes me cautious about recommending it for small gardens. Because it is a handsome tree, it is often planted as a street tree. An added benefit is its tolerance to pollution, and its shallow roots don’t raise footpaths. For a more detailed description of the leaves, flowers and seed pods, click to this Flora bank link Practical uses for the tree and its timber Its dense foliage makes it an ideal tree to plant for shelter on farms and as an understorey planting near remnant tall eucalypts like Yellow Gum and River Red Gum. Like all wattles, Lightwoods fix atmospheric nitrogen in the soil. This benefits all plants growing nearby. In Biorich plantations (designed for biodiversity and for income) it can be planted in clumps of 20 or more to allow for future maintenance and harvesting timber. Straight trees can be selected and ‘form-pruned’ to improve the future value of their harvested wood.  The beautiful grain of Lightwood timber ‘Form-pruning’ removes small branches from the main trunk, producing knot-free timber called clear-wood. Clear-wood is stronger and more valuable to furniture makers and wood turners because of its continuous, uninterrupted wood grain. Lightwood timber is hard, close-grained and dark brown with some pale stripes. The smaller branches and waste timber are also good firewood and are hot burning. Its lemon coloured pompom flowers in late summer provide good quality protein rich pollen for bees (crude protein is 23% - 27%).  Coolamon. Photo National Museum Australia Traditional owner uses The very hard timber would have been useful for making Clapsticks and for carving small wooden bowls like the Coolamon. Traditional Owners boiled the bark of the Lightwood to produce a lotion that was applied to wounds to aid healing. This lotion could also relieve painful muscles and bruising. The leaves and bark are rich in soap forming chemicals called saponins. These produce a foam when crushed and mixed with water and were used to stun and catch fish. Nature notes The upright branching habit of the Lightwood provides excellent roosting sites for birds. Parrots and native pigeon’s eat the seed pods and seeds. Smaller birds like Silvereyes, feed on the many insects that are attracted to the late summer pollen rich flowers. Other insect eating birds like the Black-faced Cuckoo Shrike feed on grubs found under the bark. Like many wattle species, Lightwood is prone to attack from borers and gall forming wasps. The galls appear as brown, rounded woody growths on the branches. They can indicate that the tree is unhealthy (heavy clay soil or poor drainage can cause stress) or getting old. The galls can be cut off and burnt if they become unsightly.  A tangle of dry Lightwood pods with visible glossy black seeds. Propagation from seed The most convenient method to separate the acacia pods from the seed is to shake and rub the opened pods through a common garden sieve, a few handfuls at a time. Winnowing in a light breeze will remove the fine trash that passes through the sieve with the seed. After the Lightwood seeds are collected and cleaned. They can then be stored indefinitely in a jar or a zip lock plastic bag. Always record the date and place of collection. To germinate the seed, place the seed in a cup and pour boiled water over the seeds until they are well covered. Any seeds that float can be discarded because they are infertile. Allow the water to cool, pour off the water and pat the seeds dry.  Acacias are best transplanted at a very early stage after germination Sow in a shallow tray and cover the seed with potting mix. They should start to germinate within two weeks. Transplant into cells or forestry tubes when they are small and easy to handle. Add a pinch of slow release native plant fertiliser.
Inoculating with rhizobia will increase the vigour and health of your trees when they are planted on in the field. Click here and scroll down for an easy acacia inoculation method. Grow plants on until they are about twice the height of the tube/cell and well hardened-off (toughened). |
Stephen Murphy is an author, an ecologist and a nurseryman. He has been a designer of natural landscapes for over 30 years. He loves the bush, supports Landcare and is a volunteer helping to conserve local reserves. 
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