Wattles, also called acacias, are wonderful native plants. More than 850 species of wattle grow in Australia, ranging from ground covers and charming shrubs to giant trees that provide fine timber and screening. With this number of species and many cultivars there is a wattle for just about any garden in Australia.
Most wattles are quick growing, short-lived plants that will usually last for about seven to 12 years. Some species however are longer lived. If planted in a thicket, they will self-sow, which will mean that short lived plants are quickly replaced. Wattles are tolerant of a broad range of conditions.
To view wattles at the peak ‘Burke’s Backyard’ visited Mount Annan Botanic Garden in south-west Sydney (about 60 to 90 minutes from the city centre). Late winter and early spring are peak viewing times for wattles.
Seed tip
It has been discovered that seed can remain viable (that is able to be grown) for more than a century. At Mount Annan Botanic Garden there are some plants which were grown from seeds that were collected in 1890, more than 100 years ago.
As they grow fast and grow readily from seed wattles are great colonisers or pioneers. They are a good plant to use to get a garden started from scratch and providing instant screening or ground cover.
Wattles are also adapted to cope with hot dry climates. Most have modified leaves which reduce water loss. Technically these leaves are not true leaves but are leaf-like phyllodes.
Winter flowering
While there are wattle species which flower throughout the year, the winter-flowering species are particularly attractive in the landscape, where their bright yellow or cream flowers bring colour to the garden at a time when many of the more traditionally grown plants are bare or not flowering. One of Australia’s most popular wattles is Acacia pycnantha, which is the official Australian floral emblem.
Biology lesson
Wattles are fascinating plants for their flower colour and foliage but also for their intimate relationship with ants. Some wattles produce little nectaries at the bases of their leaves. These provide food for ants. Other wattles produce food on their seeds, so that ants collect the seeds to eat the food and so spread the seeds around, thus propagating and spreading the wattle.
Wattle varieties in Australia
Below are a selection of wattles which are suited to a wide climatic range.
Trees
Acacia baileyana, Cootamundra wattle (see climate map 2): A tree to 6m (18′) with ball flowers June-September, grey green fern-like leaves. Other forms:
- A prostrate or ground cover form
- Variety, ‘Purpurea’, with purple new foliage.
- Acacia pycnantha, golden wattle (see climate map 1): A tree to 8m (26′) but often smaller, with green foliage and fragrant golden yellow flowers in late winter or early spring. This is the national floral emblem. It can cope with dry and arid conditions and will thrive in all but the hot tropical and coldest climatic zones.
- Acacia macradenia, zigzag wattle (see climate map 2): A weeping variety that comes from Queensland, grows to 6m (20′) and has an unusual zigzag branching habit.
- Acacia iteaphylla, Flinders Ranges wattle (see climate map 1): Both weeping and prostrate forms are available. Has perfumed flowers and grows to 5m (16′) for a good hedge or a dense ground cover.
- Acacia cultriformis , Knife-leaf wattle (see climate map 1): A shrub to 4m (12′) with ball flowers in spring, blue-green triangular phyllodes, is hardy and will grow in temperate areas. This also comes in a prostrate form which grows nicely overhanging a wall.
- Acacia chinchillensis (see climate map 1): A small wattle from Queensland which grows to 2m (6′) and fits well in a small garden. Best in a dry to hot area with low humidity.
- Acacia cardiophylla, Wyalong wattle (see climate map 1) A shrub or small tree to 5m (16′) with grey foliage which also comes in a prostrate form.
Sowing seed
Most wattle seeds can be sown in spring or early autumn into clean plastic pots, seed trays or any plastic container with holes for drainage punched through the bottom. A good potting mix is 1 part washed coarse river sand: 1 part peat moss, or any mix that will re-wet easily, drains well and is coarse enough for good aeration and drainage. To plant seeds simply scatter them over the mix and lightly cover with mix.
Once wattle seeds have grown their first true leaves they can be transferred into a tall pot. A cardboard milk container is a good shape for growing wattle seedlings.
Maintenance
Fertilising wattles is not generally considered necessary. Mulching should be undertaken to conserve moisture, keep the roots cool, restrict weed growth, reduce soil compaction and improve soil texture. Water only when plants are young or when older plants are showing signs of distress in a very dry period. Regularly tip prune young plants to encourage more compact bushes and prune regularly after flowering, unless seeds are required.
Buying wattles
Check with your local nursery or local forestry commission nursery to see which species of wattle are best in your area. For the prostrate forms check with a specialist native plant nursery.
Take care when selecting plants from a nursery. Wattles have vigorous root systems so avoid large plants in small pots or plants with roots growing through the bottom of pots as they may be root bound and will not grow as well as a younger, smaller plant when put into the ground.
Further information
Mount Annan Botanic Garden, Mount Annan Drive, Narellan, NSW, 2567. Phone: (02) 4648 2477. (Open daily, picnic grounds and visitor centre, admission charged for vehicles.)
