Wednesday, July 14, 2010
Australian native plants: Wattle Banksia.
Winter is a beautiful time of year here in the sub tropics of Australia. The nights are cool and brisk, but the days are sunny, clear, and warm ( about mid twenties in celsius degrees). I love this time of year, no humidity and it often feels like we have skipped winter, and gone from Autumn directly to spring. This is my morning view.
At least when I look out my window, I see the beautiful specimens of Wattle ( Acacia species ) and Banksia Giant Candles). Banksia plants come in many varieties and were named about the Botanist on board Cook's ship the Endeavour when it discovered the East coast of Australia in 1770. Banks and his colleagues made many drawings on these glorious plants, and thus were named after him.
Banksia have an interesting adapatation to the harsh Australian climate. They do not have flowers, but instead a large cone that holds nectar ( food for the many lorikeets and nectar feeding birds). Following this, the cone develops into a seed pod, protecting the valuable seed within until it is one day exposed to high intensity heat (such as found in a bush fire). Upon being burnt, the seed cone will open, releasing the seed contained within. The Banksia plant is then free to germinate in not only a potash rich soil, but in an area with very little competition from other plants for sun and moisture.
Which is really clever and definitley something to ponder about: the resilience and endless adaptation of nature.
Australia's official national floral emblem, featured on the coat-of-arms. Possibly the best known amongst the Australian plants. With 600 or more kinds of wattles, they can be found in every part of the country, from well-watered areas to the arid Centre to the cold mountain regions. They are usually the first to appear after bush-fires. They can be found growing in the most remote areas, from low, spreading shrubs to large, upright growing trees. The individual flowers are always very small and massed together in pom-pom heads or rod-like spikes.
1st September is Australia's Wattle Day. Whilst most wattles are spring-flowering, there are some that bloom all year round.
Wattles belong to the genus Acacia, in the Mimosa family.
There are over 600 different species distributed throughout Australia with shapes varying from low, spreading shrubs to large, upright trees. It is often called 'Mulga'. Whilst most are early spring and summer-flowering, there are wattles that bloom all year round.
Wattles are the most widespread of all Australian plants, some inhabiting the most remote and inhospitable areas, growing in parched sand in the desert under the scorching sun, spiked, hard and leafless. In the rainforest gullies they have soft feathery foliage with pale golden heads.
One species of wattle, Acacia pycnantha, is the floral emblem of Australia and is featured on the coat-of-arms.
Wattle seeds are carried in pods which twist and snap open when crisp and dry, scattering shiny, black seeds; the pods then remain on the plant. The pods are decorative, coiled and looped and twisted. The seeds have a very hard outer covering. Once released, the seeds retain viability for many years. Like many other Australian plants, the wattle has defences against drought or fire, and needs heat to release seeds or allow them to germinate.
The first leaves from the sprouting seed are always feathery and bipinnate, though later they may change dramatically. Some wattles retain their feathery foliage when adult. Others replace it with leaf-like phyllodes. These are flattened stalks which perform the function of leaves; they are tougher than true leaves and better able to withstand the arid conditions of many parts of Australia.
Foliage ranges from dark to reddish green to greyish green and silvery grey.
The flowers range in colour from cream, pale yellow to deep orange, The flowerhead is made of many small flowers with numerous stamens which create the fluffy appearance. They are massed together in pom-pom heads on short or long stalks or in spikes.
Despite the popularity of native plants in Australian gardens, the growing of wattle has never been widespread. Whilst they are fast growing they do have a short lifespan. They are useful hedge or screen plants.
Wattle is grown from seed. Acacia seed has a very tough coat which must be treated before sowing. For the seed to germinate water must be able to enter the seed. Put the seeds into a dish, pour boiling water over them, leave them overnight, and sow the next day. The boiling water simulates the heat of a bushfire, which prompts wattle germination in the bush. Sow seeds into a 50/50 mix of sand and peat moss. After watering the pot, cover with plastic to create a miniature glasshouse. After the seeds have sprouted remove the plastic and resume watering the seedlings regularly but lightly.
Acacias develop long tap roots very quickly and should be transplanted from the seed bed very early to avoid damage to the roots. In most places autumn is the best time to sow acacias to avoid transplanting in humid weather to prevent fungal attack.
Caring for Wattle
Fertilizers must be used carefully. Some acacias are very sensitive to high levels of phosphorous in the soil.
Acacias respond well to light pruning immediately after flowering to maintain a reasonable shape and to extend life. Wattles can escape from gardens and invade natural areas. For this reason some of the species available commercially may not be the most suitable for home gardens. A careful selection of suitable species should be made. Generally, it is preferable that shrub-sized species be selected. Many wattles will respond to tip pruning after flowering and before new growth commences to maintain a reasonable shape and to extend the life of the plant.
Wattles can be beneficial as garden plants. Because of their fast growth rate and tolerance of full sun, they can provide protection and shelter for other young plants. They also aid the growth of other plants by contributing to the nitrogen content of the soil.
The main pests are borers but galls can be a problem on the smaller branches and on the pods.
The word 'Wattle' is of Anglo-Saxon origin and refers to flexible lengths of branches woven between stakes for the construction of fences or walls, 'wattle and daub' construction, with an additional layer of mud or clay to weatherproof the house walls. The huts of the early settlers were made using this 'wattle and daub' technique. The Acacia branches were found to be the most suitable and these trees soon came to be called Wattles.
Aborigines used the seeds of several species as a source of food. Some species are toxic.
This info was adapted from the following page: