Australian Natives I

Course CodeBHT113
Fee CodeS2
Duration (approx)100 hours
QualificationStatement of Attainment

 

Be an Australian Native Plant Expert.

  • Learn to identify hundreds of different plants
  • Discover the potential of Australian Plants for Garden Design, Cut Flower Production, Culinary and other uses
  • Learn the unique cultural needs for growing Australian Plants, anywhere in the world
  • Indulge a passion, explore a whole new world in gardening, or improve your career opportunities

Australian native plants are increasing in popularity in many countries throughout the world and are grown commercially as cut flowers in Israel and South America. Eucalypts are widely planted trees throughout California, and is an increasingly popular specimen tree used in gardens of Southern England. Macadamia nuts and Tea Tree Oil are produced in commercial plantations not only in Australia, and beyond. Many Australian natives are also well suited as indoor plants.

Australian climatic conditions range from hot-dry to cold-wet; soils also vary according to region from alkaline to acidic. Consequently the plant life of this large country is abundant and diverse, offering an interesting range of possibilities, whether you live in Australia or elsewhere.

Lesson Structure

There are 9 lessons in this course:

  1. Introduction
    • Scope and Nature of Native Plants
    • Taxonomy: Botanical and Horticultural Nomenclature
    • Binomial System
    • Levels of Division
    • Plant Families
    • Species, Hybrids, Varieties and Cultivars
    • Botanical Keys and their Use
    • Origins of Australian Plants
    • Continental Drift
    • Resources for More Information
    • Sources for Seed Information
  2. Cultural Techniques
    • Cultivation
    • Things that can Go Wrong: Pests, Diseases, Environmental Problems, Nutrition
    • Soils
    • Improving Soil Structure
    • Soil Water Management
    • Compost
    • No Dig Growing Techniques
    • Feeding Natives
    • Pruning
    • Temperature
    • Planting, Staking, Mulching
    • Special Planting Techniques
    • Natives for Shade
    • Controlling Weeds
    • Propagation; seed, cuttings, etc
    • Stock Plants
  3. Eucalypts
    • Introduction
    • Types of Eucalypts; gums, stringybarks, boxes, ironbarks, yates, peppermints, etc.
    • Hybrid Eucalypts
    • Eucalypt Cultural Requirements
    • Review of Important Eucalypt Species
  4. Native Trees
    • Casuarina; Casuarina and Allocasuarina, Gymnostoma and Ceuthostoma
    • Casuarina Culture
    • Review of Casuarina and Allocasuarina species
    • Australian Conifers: Overview
    • Cupressaceae: Actinostrobus, Calitris, Diselma
    • Araucariaceae; Araucaria
    • Podocarpaceae; Dacrydium, Microcachrys, Microstrobos, Phyllocladus, Podocarpus
    • Taxodiaceae:
    • Macadamias
    • Brachychiton
    • Angophora
    • Lophostemon
  5. Acacias
    • Introduction to Legumes; Papilionoideae, Caesalpiniodeae and Mimosoideae
    • Overview of Acacia
    • Acacia Cultural Requirements
    • Review of Important Acacia species
    • Elements of drawing a Landscape Plan
    • Landscape Design Procedure
  6. Myrtaceous Australian Plants
    • Review of the Myrtaceae Family
    • Callistemon overview
    • Callistemon Culture
    • Important Callistemon cultivars and species
    • Leptospermum overview and Culture
    • Important Leptospermum Species
    • Baeckea
    • Calothamnus
    • Calytrix
    • Eugenia
    • Homoranthus
    • Kunzea
    • Melaleuca
    • Micromyrtus
    • Scholtzia
    • Syzygium
    • Verticordia
    • Thryptomene
  7. Grevilleas
    • Grevillea Overview
    • Types of flower: Erect Cluster, Toothbrush, Pendant, Cylinder
    • McCilveray’s Classification into eleven main groups
    • Flower and Leaf Terminology
    • Review of Low Growing Grevilleas
    • Banksia Type Hybrids
    • Hybrid Parents from tropics and sub tropics
    • Poorinda Hybrids
    • Review of many Important Species
    • Culture
    • Related Proteaceae Natives: Dryandra, Hakea, Banksia, Telopea
  8. Ground Cover and Small Shrubs
    • Overview of Fabaceae (Egg and Bacon) Plants
    • Brachyzema
    • Castenospermum
    • Clianthus
    • Gastrolobium
    • Gompholobium
    • Goodenia
    • Hardenbergia
    • Hovea
    • Jacksonia
    • Kennedya
    • Oxylobium
    • Swainsonia
    • Viminaria
    • Boronia; overview and culture
    • Boronia species
    • Prostanthera
  9. Commercial Applications
    • Fragrant Natives
    • Uses for Eucalyptus
    • Uses for Grevilleas
    • Uses for Acacia: timber, tanning, cut flowers, food, etc
    • Aboriginal Uses for Acacias
    • Growing Natives in Containers
    • Bush Tucker

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

  • Classify most significant cultivated native plants, to the family level.
  • Determine cultural practices to maintain healthy native plants.
  • Explain the identification and culture of eucalypts in your locality.
  • Explain the identification and culture of native trees.
  • Explain the identification and culture of acacias in your locality.
  • Explain the identification and culture of native shrubs, including species of Acacia, Melaleuca, Callistemon and Leptospermum
  • Explain the identification and culture of different Proteaceous native plants, with particular emphasis on the genus Grevillea.
  • Explain the identification and culture of a range of Australian Native ground covers and small shrubs.
  • Determine commercially viable applications for different native plants.

WHY CHOOSE TO GROW AUSTRALIAN PLANTS?

Australia was one of the last places on earth to have i's plants explored and brought into cultivation. Man has been growing and developing plants from Asia, the Americas, Europe and Africa for hundreds of years; but most Australian plants weren't even considered for cultivation until the last century.

This means that Australian plants are largely undeveloped. The range of plants that come from Australia is huge; and because they have not beenbred and selected very much; the commercial potential for these species is on the whole, much greater than the potential you might find with plants from elsewhere.

We mostly use Australian native plants as garden specimens but they have many other valuable domestic and commercial uses. In the home garden we grow native plants to attract birds and wildlife. Native plants are also grown for their distinctive flowers, foliage and fruits which are highly valued by florists and crafts people. Other useful products from native plants include essential oils, bush tucker and timber.

 If you want an exciting future in plant breeding; or an opportunity to create landscapes that look different to any other landscapers; consider exploring the potential of Australian plants. This course guides you along just such a pathway.

 

USING NATIVES AS CUT FLOWERS

While kangaroo paws and Geraldton wax have been used as cut flowers for a number of years, there are numerous other native species that are ideally suited as cut flowers. Many Australian plants have unique flower and foliage forms, quite unlike any of the traditional flowers used by florists. Plants with extraordinary flowers like the Gymea lily, waratahs, grevilleas, dryandras and banksias are now in demand for both local and overseas flower markets. The fact that many species have long flowering periods, extended vase life, strong stems, and are excellent bouquet ‘fillers’, also makes them valuable as cut flowers.

The most commonly grown native plants for the local cut flower industry are kangaroo paws, Geraldton wax, thryptomene, boronia, banksia and waratah. Other plants that are in demand for flower export are stirlingia, koala fern (Caustis blakei), scholtzia, Christmas bells (Blandfordia), Christmas bush (Ceratopetalum gummiferum), flannel flower, eriostemon, riceflower, cryptandra and eucalyptus foliage.

Until fairly recently, most native flowers were cut straight from the bush. As natural populations have dwindled and demand for reliable supplies have grown, many cut flower varieties are now cultivated in plantations. A few species that have shown promise as cut flowers have undergone intensive development to create improved cultivars; for example, there are more than fifty named cultivars of Geraldton wax.

Growing Native Plants for Cut Flowers

Native plants that are grown specifically for their flowers and foliage need the following conditions:

 Plants grown commercially are planted in rows that allow good access for machinery. Plants must be monitored and treated for pests and diseases, as only top quality, blemish-free flowers and foliage are acceptable for the florist trade.

Australian Plants to Consider Growing as Cut Flowers

Focal Flowers
These are the large colourful flowers that form the centrepiece of an arrangement:

 Flower Fillers
Usually (but not always) flower fillers have branches with many small flowers:

Foliage Fillers
Foliage fillers are plants with unusual, attractive, and long leaves:

 Woody or Unusual Seed Capsules

Dried Native Flowers
Some native cut flowers are dried and even dyed to enhance their longevity and usefulness in floral arrangements and in craft.

Most dried flowers are produced in Western Australia. These include banksias, verticordia, stirlingia and dryandra. After harvesting they are processed by a variety of means, including air drying, bleaching, dyeing, preserving and freeze drying.

 

EDIBLE AUSTRALIAN PLANTS

Hundreds of different plant species were used as a food source by Australian Aborigines. Nowadays we are familiar with just a few of those plants, although interest in bush tucker is undergoing a revival of interest as both home gardeners and commercial growers are discovering the diverse range of edible native plants.

The best known edible native plants are macadamias and Davidson’s plums, both of which grow naturally in subtropical rainforests along the northern coast. The ‘bush nuts’ (Macadamia integrifolia and M. tetraphylla) once gathered by Aborigines are now rare in the wild but have been bred for a number of years (mainly in Hawaii) to produce superior varieties that are grown in large commercial plantations. Trees grow 12 to 15m but smaller grafted varieties are available. The trees are slow-growing and require deep, well-drained and enriched soil. They need a protected position as they are sensitive to frost, winds and drying out. The nuts can be eaten raw or roasted.

Davidson’s plum (Davidsonia pruriens) is an attractive small tree that produces a sour plum-like fruit. The fruit are used to make jam, conserves and wine, and as a flavouring in sauces and drinks. The tree requires shelter from winds and frost, and adequate water during the growing season.

Bush Tucker Plants
Some bush tucker plants are harvested from the wild but as demand is increasing more varieties are being cultivated. Most bush tucker is minimally processed or value-added (for example, as dried spices or in sauces); only very small volumes are sold and consumed as fresh produce.

Quandong (Santalum acuminatum) A shrub or small tree with a wide distribution in semi-arid regions of southern Australia. The tart-tasting fruit can be eaten fresh although it is more commonly dried and then reconstituted for use in sauces, preserves, chutneys, liqueurs and dipping sauces.

Lemon myrtle (Backhousia citriodora) A rainforest tree that grows to 15m in its natural environment. The leaves have a strong lemon scent and are used to flavour a wide range of sweet and savoury foods. They are also used in non-food products such as cosmetics and household cleaners.

Native limes There are six species of true native citrus, as well as a number of hybrids. Until recently most native limes were harvested from wild populations of the desert lime, although commercial orchards are now starting to meet the growing demand from restaurants and food processors. These include the following:

Bush tomatoes (Solanum centrale) Also called the Desert raisin or Desert tomato, this small shrub occurs naturally in central Australia. The green fruit are toxic and must be not be eaten. The ripe fruit is dark brown and has a globular raisin-like appearance. The fruit is usually dried, either on or off the bush, then used sparingly to impart an intense piquant flavour to sauces, marinades and chutneys.

 Wattle seeds Although a large number wattle species have edible seeds, the Elegant wattle or Gundabluey (Acacia victoriae) is the most commonly harvested species for the bush tucker industry. A. victoriae is a spiny-stemmed shrub or multi-stemmed tree to 3-4 m tall. The glossy, dark brown seeds have a nutty flavour after roasting*. They are high in protein and are gluten-free, which makes them suitable for speciality diets. The roasted seeds are normally ground to a powder then added to breads, biscuits, cakes, sauces and icecreams.

Many raw acacia seeds contain toxic compounds and have properties that inhibit enzymes in the digestive system. Seeds that are known to be edible should be roasted before consumption.

Riberry (Syzgium leuhmannii) A rainforest tree that grows to 30m in its natural environment but in cultivation rarely exceeds 10m. The red/pink berry-like fruit has a strong spicy flavour. The fruit is used in icecreams and sauces for meat dishes.

Mountain pepper (Tasmannia lanceolata) A medium to tall shrub from cool, moist forests in Tasmania Victoria and southern NSW. Both the glossy, dark green leaves and the small dark berries are used as a hot, savoury spice in mustards, cheeses, sauces, breads and other savoury foods. Separate male and female trees are need to produce berries. The berries, produced only on the female trees, can be dried, ground or preserved in brine.

Warrigal greens (Tetragonia tetragonoides) Also known as New Zealand Spinach, this rambling green prostrate herb grows in many parts of Australia. It is regarded as an agricultural weed in some parts of Queensland. The plant grows quickly and is short-lived. The arrow-shaped leaves have a spinach-like flavour and are used in the same way as traditional spinach and Asian greens. However, they must be used with caution as the leaves contain high levels of oxalates. Only eat the leaves and young stems, and blanch them for 3 minutes before use to remove the soluble oxalates. The water should be discarded.

Muntries (Kunzea pomifera) A prostrate or semi-upright shrub from drier regions of southern Australia. The greenish-purple fruit, up to 1cm diameter, have a spicy apple flavour. Fresh fruit is used to make jams, added to fruit salads, and in sweet and savoury sauces. Trellising is used in commercial plantations to overcome problems caused by the plant’s prostrate growth habit.

 

GROWING NATIVES FOR TIMBER

Native trees are grown and harvested to provide building and furniture timber, fencing and pole timber, pulpwood, firewood and fodder.

The best known Australian native trees, the eucalypts, are grown extensively for timber and paper pulp production, both in Australian and overseas plantations. Their main disadvantage is the long period of time required to produce a harvestable crop. For example, mountain ash (Eucalyptus regnans) typically takes more than fifty years before it can be harvested. Other species, though, can produce commercial timber in a shorter period; for example, spotted gum (Eucalyptus maculata) can be harvested in less than twenty years.

Blackwood (Acacia melanoxylon) and black wattle (A. mearnsii) have potential as timber for furniture, joinery and pulp. They are also excellent for controlling erosion. Both require adequate rainfall to be suitable for use as timber.

In subtropical and tropical areas, the main plantation timber is the Hoop pine (Auracaria cunninghammii), although other rainforest trees, such as red cedar (Toona australis), coachwood (Ceratopetalum apetalum) and Crows ash (Flindersia australis), are also regarded as important timber species.

In drier, inland areas, valuable native timber species include callitris, casuarinas, ironbark (Eucalyptus sideroxylon), river red gum (Eucalyptus camaldulensis) and acacias.

 

EXTRACTING ESSENTIAL OILS FROM NATIVE PLANTS

The flavour and fragrance of scented plants such as lemon myrtle, eucalypts and boronias is due to the aromatic compounds in their flowers, leaves and bark. When these are extracted by distillation, the resulting product is a volatile, colourless, oil-like material. Essential oils are used in food flavouring, and in the cosmetics, pharmaceutical and fragrance industries.

Two native plants are harvested commercially for their essential oils: eucalypts and tea trees. Eucalyptus oil is mainly extracted from the blue mallee gum (Eucalyptus polybractea), a deep-rooted tree from the mallee regions of Victoria and NSW. The oil from this tree is used in inhalants, soaps, lozenges and other medicinal products. Other species used to produce medicinal oils include E. globulus, E. dives, E. sideroxylon, E. viridis and E. leucoxylon. Eucalypts used to produce industrial oils (to make disinfectants and industrial cleaners) include E. dives, E. radiata and E. elata. The lemon-scented gum (Corymbia citriodora) has been used to supply citronella oil. The production of eucalypt oil has a long history – the first eucalypt distilleries were operating in the early days of colonial settlement.

Tea tree oil is mainly extracted from a small paperbark tree (Melaleuca alternifolia) that grows naturally in damp soils in northern NSW and Queensland. Oil production commences in 12-18 months after planting, and the harvest continues on a 12-18 month cycle for up to ten years.

Other native plants that yield essential oils include the brown boronia (Boronia megastigma), mountain pepper (Tasmannia lanceolata), lemon myrtle (Backhousia citriodora) and native frangipani (Hymenosporum flavum).

The yield of essential oil is usually very low in relation to the amount of plant material used. Depending on the quality of the plant and the distillation method used, yields of between 0.005% and 5% may be obtained. For most plants, the oil is extracted by stem distillation, which involves placing the plant material on a mesh surface in a closed still. Steam pumped into the still 'boils' the plant material very quickly and releases the aromatic compounds as a vaporised oil. The vapour is rapidly cooled in a condensation chamber, causing the vapour and steam to liquidise and separate. Modern essential oil producers may perform this process under a partial vacuum. This reduces the boiling point of the steam, allowing a 'cooler' distillation which does less harm to the more fragile fragrance components.

We mostly use Australian native plants as garden specimens but they have many other valuable domestic and commercial uses. In the home garden we grow native plants to attract birds and wildlife. Native plants are also grown for their distinctive flowers, foliage and fruits which are highly valued by florists and craftspeople. Other useful products from native plants include essential oils, bush tucker and timber.

 


 

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