Selecting plants for central Australian gardens – technical tips from Geoff Miers, Feb. 2013
Story kindly provided by Geoff Miers, Geoff Miers Gardens Solutions, Alice Springs for RIG News, February 2013
Having experienced one of the hottest summers in Central Australia on record with Alice Springs experiencing 21 days in January alone between 40 to 46 degrees, home gardens have surely been tested, with universal plant casualties in literally every garden. Interestingly it’s been rare to see a dead Central Australian plant species. They have coped well while even the hardiest Australian plant species from elsewhere have suffered greatly. Surely there is a lesson to be learnt from this. Two decades ago there were few Central Australian plant species available commercially through local nurseries. Today however, there exists a wide selection of trees, shrubs, ground covers, grasses and bush tucker plants.
Consider these sorts of options – a combination of small to medium Eucalypts and Acacia along with trees like the Whitewood Atalaya hemiglauca, Kurrajong Brachychiton gregorii, Grevillea striata or Beefwood and the small but delightful Santalum acuminatum or Quandong tree.
Amongst my favorite local Eucalypts are the tall growing Thozet’s Box Eucalytpus thozetiana, the small Shiney-leaf Mallee Eucalyptus lucens and the Round-leaf Mallee Corymbia orbifolia with its red mottled bark and bluish-grey foliage.
Amongst the wattles its hard to beat the tough old Mulgas such as the Common Mulga Acacia aneura and the Red Mulga Acacia cyperophylla (two excellent small to medium trees) and the Witchetty and Umbrella Bushes Acacia kempeana and Acacia ligulata, respectively, as two drought survivers, and the rapid growing broadleaf Candelabra Wattle Acacia holosericea.
The native fuchsias or Eremophila species are largely unknown plants however they are generally tough, drought tolerant and great bird attracting plants. Eremophila bignoniflora is a small tree, Eremophila christopheri and Eremophila freelingii are great hill-side plants while the vast range of Eremophila maculatas or Emu Bushes can bring red, orange, lilac, purple and yellow blooms to the garden.
If you’ve got a dry, hot spot with clay soils consider Eremophila polyclada. This is a medium size shrub that flowers continuously from Spring right through to late Autumn and no matter how hot it gets during summer it continues to flower at its peak.
All plants introduced into Central Australian gardens need to be watered well initially and as they are established. As plants get established, the watering regime needs to change – allow for less frequent waters but for longer periods in order to promote deep rooting. A deep rooted plant is much more able to withstand periods of drought.
The most efficient system to install is a drip irrigation system as this places water right where it is needed. The polypipe should be buried 100mm below the surface with 4mm feeder line bringing the emitters to the surface. A 1-31 day battery operated irrigation controller will provide the flexibility required to develop a watering regime that will water daily as required initially to up to 30 days once plants have become established.
To compliment a drip irrigation system, mulch should be applied to most garden beds or applied to the immediate area around individual plantings. Where termites are a problem use non-organic mulch like sand, pebbles and rocks. These mulches will all help conserve the water applied, moderate soil temperatures and reduce weed growth.
In the home garden other organic mulches can be applied and while acting as a decorative surface treatment they also help reduce water loss through evaporation, moderate soil temperature and reduce weed growth. Soft organic material like pea straw, Lucerne and sugar cane mulch are also excellent as they break down relatively quickly providing valuable nutrients and organic content to the soil.
In dry Inland Australia organic content is often lacking and most soils need regularly to have organic material added to stimulate all the necessary microbes and fungi, etc in the soil needed to break down the organic content releasing much needed nutrients to sustain healthy plant growth.
There are many plant species that can be purchased in nurseries today and most are sold on the strength of a colourful plant label, irrespective of whether they are suitable for your soils or climatic conditions. Don’t purchase on impulse, learn to understand your local environment, look to see what is growing well in your region and seek local expert advice before becoming a victim to the impulse buying based on a colourful label.
Thoughtful plant selection and adapting gardening techniques to suit arid land conditions will reward you with a healthy garden that doesn’t experience massive plant losses when hot summers and freezing winters are experienced.
If we believe in global warming then more climatic extremes are likely to be experienced in the decades ahead and gardening will become tougher unless we adopt a common sense approach to gardening that is reflective of soil, climatic and environmental conditions.
From RIG News, February 2013