ACACIAS VHT114

Learn about Wattles

Learn about the identification and botany, and culture (planting, watering, feeding, propagation)
of the wattles. Around 50 species are studied in detail. You also learn about the commercial uses of Acacias as building materials, food plants, for tanning, craft, etc.

Acacias have more uses than most people realize. The most obvious use is as a garden plant; or perhaps a timber. Acacias are also grown and harvested for a whole range of purposes.

Did you realize that Gum Arabic comes from Acacias?
Did you realize that some African tribes use Acacias as a major food source for livestock?
Do you realize, some Acacias are used to supply medicines?
Do you realize native peoples in Australia, Africa and other places eat seeds, flowers, gum and other things harvested from Acacias

Learn to Grow and Use Acacia Plants

Acacias come in all sizes -trees, shrubs; even ground covers
As legumes they build soil fertility
As fast growers, they are great for establishing a new garden faster
The seed is edible; gum is harvested commercially in some parts, wood of some is used for construction.

Course Structure

There are 8 lessons in this course:

Introduction and Resources.
Physiology and Botany of Acacias.
Culture - planting, mulching, pruning, etc.
Propagation
Acacias And Their Uses - Windbreaks, erosion control, soil enrichment, tubs.
Other Uses For Acacias - Timber, craft etc.
Pest & Disease of Acacias
Special Project

Aims

To describe the way in which Acacias are classified.
To determine how to find reliable resource information that relates to Acacias
To describe the physiology of Acacias
To determine cultural requirements that are common to Acacias
To determine propagation methods that are commonly applicable to Acacias.
To describe a variety of commercial uses for Acacias.
To describe a range of other practical uses for Acacias.
To identify and recommend treatment for a variety of health problems occurring with Acacias.
To develop an in depth understanding of one aspect of Acacia Growing.

Duration: 100 hours

An Introduction to Acacias

Genus: Acacia
Family: Mimosaceae
Common Name: Wattle

Origin: Around 1,350 species from Australia, and parts of Africa, Asia and America.
Note: A reclassification by some scientists has split this genus into three: Acacia, Senegalia and Vachellia. Acacia still encompasses mostly the Australian species.

Appearance: Evergreen and deciduous trees and shrubs (genus includes a few herbs); flowers occur mostly in spring or winter and are most commonly yellow fluffy balls (due to multiple long stamens) or cylinders (bottlebrushes); fruits are dry pods containing a number of hard black seeds when ripe; leaves are often bipinnate and sometimes phyllodes (leaf-like stalks which act as leaves).

Culture: Fast-growing. Cultural requirements are varied. Select species appropriate to the location. Many will grow across a wide range of soils. Many require a lot of space. Generally avoid waterlogging, but increase watering over spring and summer. Heavy pruning can result in dieback; so only prune lightly, and when necessary. Some live to over 100 years, but most are much shorter-lived, many living less than 20 years. Only evergreen species do well outdoors in cold temperate regions where they prefer sheltered sites.

Propagation: Seed. Place seed in a container and pour near boiling water over the top, soaking until water cools then plant. This breaks the seed coat and hastens germination. Sow seed in mid spring.

Health: Many species are hardy in a climate similar to their indigenous environment. Some are drought-hardy, some are cold-hardy, some tolerate wet soils better than others. They can suffer fungal galls, wasp galls and rust galls, borers can attack many species. Root mealy bugs may cause wilting. Beyond that, many other problems tend to occur on some but not most species.

Uses: Shade tree, feature tree, shrub, occasionally a cut flower, land rehabilitation, screening plant; occasionally as a tub plant.

Cultivars/Species:

Acacia baileyana (Cootamundra Wattle): One of the more commonly grown Acacias used in landscapes and home gardens across South Eastern Australia; a large bush or medium size tree that will grow taller when competing for light. A purple tipped form and low growing forms are also available. The species has extremely attractive bipinnate (feathery) foliage; and grows rapidly in a wide variety of soil types. Can be short-lived; often only 10 to 15 years. Older plants may survive but become unattractive and/or infected with borers.

Acacia dealbata (Silver Wattle): Sometimes a shrub, normally a tree; up to 30 metres high. Yellow ball flowers in heads (17 to 35 balls per head); whitish appearance to younger branchlets; is cultivated both within its native Australia and beyond as a landscape plant. Has attractive silver to glaucous (i.e. blue-green) foliage.

Acacia decurrens (Sydney Wattle, Early Black Wattle): Bipinnate, feathery leaves; grows up to 10 metres tall, but often less. Good for tanning (bark contains up to 40% tannin). Flowers can be used to produce a yellow dye; wood is commercially useful; flowers are edible and have been covered with batter and cooked as ‘fritters.’ Gum is edible; but generally considered a poorer quality gum Arabic substitute.

Acacia longifolia: A common landscaping plant used across much of south eastern Australia; Good windbreak; Can be relatively short lived (perhaps 15 to 20 years)

Acacia mearnsii (Black Wattle): A useful timber in Australia, particularly valued for craft and furniture; excellent plant for stabilising eroding soil. A native of Australia, this is a significant weed species in South Africa. Fast-growing tree or large shrub, 6 to 20 metres tall; dark olive green bipinnate leaves; flowers cream or yellow, fragrant balls in large clusters.

Acacia podylaerifolia: To 4 x 3m, blue-green foliage, entire leaves; golden ball flowers are produced over winter and into spring. A native to the subtropics, but will grow in temperate climates including Melbourne.
Acacia Senegal: One of several species harvested for commercial ‘gum Arabic.’ Commonly grows 2 to 4 metres tall but occasionally as a tree to 9 metres tall. Bark is greyish-brown to yellow-grey; spiny plant with black thorns occurring in threes, the middle one curved; pods are brown and papery. Red flower buds open to produce cream to white coloured spikes either single or in groups of 2 or 3. Wood is used for construction or fuel. Foliage is often used as fodder for camels and goats.

Acacia tortilis: Indigenous to large areas of Africa and the Middle East including Israel; many varieties only some 4 metres tall, but others up to 15 metres; white, fragrant flowers, thorny foliage is grazed by wild animals and attacked by a variety of insects. Well-suited to arid climates; commercial plantings commonly on a 3 X 3 metre grid used for timber, fuel and a range of other purposes, in Arabia and some other places. It’s palatable to animals and used widely for fodder. Used for sand dune rehabilitation in India and Africa