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"Acacias for Central Coast Gardens"

Acacias, or wattles as they are more commonly known, have long been identified with Australia. The Australian golden wattle Acacia pycnantha, is our national floral emblem and is depicted on our coat of arms. Many of our sporting teams reflect the green & gold colour of the wattle in their uniforms. We celebrate wattle day on the 1st September.

In the garden
Wattles have become popular garden plants, being both attractive and generally easy to grow. Care needs to be taken to select the right wattle to grow in the garden as they can vary in size from tiny prostrate plants to 30m high trees. The foliage can be most attractive with colours from green to silver grey. The flower heads are either balls or short spikes of flowers from creamy yellow through to bright orange yellow. However, the tiny Queensland wattle Acacia purpureapetala is different – it produces purple flowers. Wattles develop seed pods after flowering. Birds such as parrots and cockatoos love the seed.
Many of the wattles grow quickly but can have a short life span, making them useful ‘fill’ plants, whilst slower growing shrubs and trees establish in the garden.
Generally wattles are very hardy in the garden, only needing good drainage and a light prune during their early growth. Borers can be a problem.

Gardens near the bush
I
n bush areas of the Central Coast there are a few acacia species that have become weed pests. If you live near a natural bush area you should avoid planting the Cootamundra wattle Acacia baileyana, the Queensland wattle Acacia podalyriifolia and the wreath wattle Acacia saligna.

Commercial use of wattle
Other than being useful garden plants,   Acacias are used for furniture making, firewood and fencing whilst the tannin from the bark of Acacia mearnsii is used for tanning leather.

Many of our acacias have toxic or poisonous seeds, however research is enabling some wattle seeds to be used in cooking.

 

  Some suggested local Acacias to grow in Central Coast gardens

  • Myrtle wattle Acacia myrtlifolia: Shrubby species with height from almost prostrate to 2m. Suit rockery and position in semi-shade. Sweetly scented lemon flowers over long period in spring.
  • Sweet - scented wattle Acacia suaveolens: Small to medium shrub, attractive perfume, long flowering. Blue-green leaves and pods. Flowers deep yellow in winter. Suitable for coastal planting.
  • Coastal wattle Acacia sophorae: Spreading shrub to 3m. high. Golden spikes of flower in spring. Useful for dune stabilising and beachside planting.
  • Sunshine wattle Acacia terminalis: Dense shrub usually to less than 3m. tall. Shiny dark green foliage, deep yellow flower balls autumn to spring. Adaptable wattle, good for frost areas, sandy soils.
  • Sydney golden wattle Acacia longifolia: Fast growing screening plant to 6m. Good for seaside gardens. Golden flowers grow along short spikes.
  • Coastal myall Acacia binervia: Grow as a large shrub or tree. Attractive grey foliage, bright yellow flowers in spring.
  • Cedar wattle Acacia elata: Very large rainforest tree to 12m. Fast growing, reasonably long-lived. Will grow in semi-shade. Large, fluffy pompom flowers, pale yellow in summer.
  • The Gosford wattle Acacia prominens: Attractive fast growing tall shrub or tree to 15m. tall. Blue grey foliage, yellow ball shaped flowers in spring. Will grow in semi-shade.

 

How to grow Acacia Seed

1. Seed of acacias, which occurs in pods, has a tough outer shell that does not allow water to enter the seed easily. Other plants with similar types of seeds include the many ‘pea flowers’ and these seeds can be treated the same way.

2. For a seed to germinate, water must enter the seed. In the case of these hard-coated seeds, we must do something extra to get the seed to grow.  For wattle and similar types of seeds, we treat the seed with boiling water before sowing it.

3. Place the seed in a cup (not plastic) or some other heat proof container and pour boiling water over it. Allow the seed to soak overnight and you should notice that some or all of the seed has swollen. Wet seeds stick together and can be difficult to separate for sowing. To make the job easier, drain off excess water, dry on a paper towel, then apply a liberal amount of talcum powder. Seed that has not swollen should be treated again.

 

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To avoid accidents children should
ask an adult to pour
the boiling water onto
the seed.

OR

An alternate to the boiling water treatment is to gently rub the seeds between two sheets of fine sandpaper.  This reduces the thickness of the seed coat and allows the water to penetrate.

 

4. The seeds are now ready for sowing. Place the seeds between sheets of moistened paper towel. Then place them in a sealed container, such as an empty margarine container, or they can be sown directly into a suitable soil mix. If you use the margarine container, you will be able to look at the seeds now and again and only plant those seeds which have germinated.   Label and date the seeds.

    Only sow swollen seeds

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If the seeds have germinated, you will    notice a white "shoot' coming out of the seed.  This is realy the first root and will soon be followed by leaves.

Store in a warm, dark place
until the seeds have germinated

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5. The seed can be placed into a small pot containing a suitable soil mix such  as 1 part of peat moss and 4 parts of washed river sand. The seed should     be just covered with the soil mix. The soil mix should be moist before you    place it in the pot.

 

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6. Place the pot in a partly shaded position and water by standing the pot in a partly filled container of water. Plants not required for the garden should be potted-on into larger pots when needed. 

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Produced by the Australian Plants Society, Central Coast Group in conjunction with
Gosford City Council and Wyong Shire Council.