Broombush

Note Number: AG0638
Published: January 2003
Updated: May 2009

 

This Agricultural Note provides information on broombush and the broombush industry.

Broombush (Melaleuca uncinata) is an attractive native shrub that is widely distributed across southern Australia, from parts of the arid pastoral zone to high rainfall areas. Broombush is a viable plantation species, requiring very little management once established when compared to other farm forestry plantings. It is traditionally used to make brush fences.
 

Site preference

Broombush is a very adaptable plant.  In low rainfall areas (250 – 300 mm) it naturally occurs on deep sands in association with ridge-fruited mallee (Eucalyptus incrassata).  In the 350 – 450 mm zone broombush grows in dense sands on soaks and in the higher rainfall areas (450 – 550 mm) broombush favours shallow sands over clay.  It can tolerate waterlogging and its roots can penetrate saline clay sub-soils. It thrives on slight rises in saline swamps just above where swamp paperbark (Melaleuca halmaturorum) is dominant.  It grows naturally on sandy and gravelly soils across the Wimmera.

Description 

  Broombush grows from 1 – 5 m tall and has many erect branches and fine needle   like leaves with bent tips.  Woody seed  capsules form in groups fused around branchlets and contain very fine seed with about 3000 – 4000 viable seeds per gram.

 Younger broombush is generally multi-stemmed, but when older, can be mallee-like or even develop a single trunk with  branches of various lengths up the stem. 

 A stump (lignotuber) forms below the soil surface with many dormant buds that reshoot after fire or cutting.  This produces  many fine erect branches that are relatively uniform in length and are particularly suitable for cutting as ‘brush’, which is used    to make high quality brush fences.

Figure 1. Broombush foliage

Products

Broombush has traditionally been used as a source of fencing material and is hand-packed by fencing contractors on site. It is more common for fencing panels to be formed with machines these days. As well as fencing panels broombush is used for garden furniture, garden shade houses, garden ornaments and hanging baskets.  It is used widely in Australia and overseas.

Figure 2. Typical bush fence	Figure 3. Plantation of broombush

Resources

For many years, broombush has been sourced from State forests and other public land throughout South Australia and northwest Victoria.  However, with the increasing focus on conservation, these production areas are gradually being closed down. In Victoria in 1989, a complete ban was imposed on harvesting broombush from public land.  It is still possible to harvest on private land but permits are required from your local council.  In fact most states have some sort of controls on harvesting broombush to ensure regeneration occurs. Local regulations need to be checked before embarking on this enterprise.

A number of landholders have started to develop commercial plantations of broombush in lieu of harvesting from native stands to ensure ongoing supply to this growing market.  An estimated 2000 ha would currently be required to fully meet demand on a sustainable basis.

There are also some indirect economic benefits of establishing broombush on private land.  These include:

• Shelter – broombush grown as a component of shelterbelts may provide shelter for stock and crops.
• Salinity control – plantations adjacent to or on saline seeps may help lower watertables and reduce dryland salinity.
• Soil erosion control – plantations of broombush can assist to stabilise hydrophobic sands, especially sand dunes that have begun to drift and actively eroding creek lines on duplex soils (light sandy soils over clay).
• Biodiversity – broombush provides a habitat for wildlife such as birds and echidnas.
• Economic – increase and diversification of farm income.

Site establishment

Broombush plantations can be established by either planting seedlings, cuttings or by direct seeding.  Each option has its own merits and disadvantages.  A profitable broombush plantation requires a high stocking rate of about 4500 plants per hectare (1.5 m spacing between rows, 1.2 m within rows).

Direct seeding

This is the cheapest method of establishment and has the advantage of high seedling density, but is generally too unreliable in areas with less than 300 – 350 mm rainfall.  Distribution may be patchy resulting in having to replant the following year to achieve an evenly stocked plantation.
The seed beds need to be moist but not waterlogged as the young seedlings are quite susceptible to over-dry or over-wet conditions in the early stages.  Severe frosts have been known to damage young bushes so it is recommended that planting should be left until after the frost season.

Seedlings

Planting seedlings is more reliable and ensures an even distribution across the plantation. However it is more labour intensive than direct seeding, and more expensive.

Cuttings

Cuttings can be taken from broombush plants that have vigorous growth and fine straight branches with acutely angled forks – perfect for packing into a fence.  A plantation of broombush propagated from cuttings is likely to significantly improve the proportion of marketable brush.  Much larger yields of brush are required however to offset the extra cost of cuttings.

Establishment

Like most tree or shrub enterprises careful planning and preparatory work will increase the chances of getting a productive stand.  It is essential to control weeds before and after planting, so spraying with a residual herbicide prior to planting is essential.  You will need to continue good weed control to ensure the bushes grow at their optimum rate.

High density planting generally produces better quality stems and out-competes weeds.

Management

Broombush plantations require very little management once established, compared to other farm forestry plantings.  As an indigenous plant, broombush is well adapted to dry conditions and can easily withstand many years of drought, although the growth rate may be reduced.

Weed control

After planting weed control will need to be maintained in the first two years.

Broombush produces a mass of lateral roots which after three to four years suppress the growth of weeds between the bushes.

Nutrition

Trials have indicated that fertiliser applications have had little effect on the height or width or general growth of broombush in the first three years of growth.  If it is applied to young plants caution is required as there is a risk of damage to the broombush plant.

Harvest

Broombush takes between 6 – 16 years to grow to harvestable size, depending on site quality, rainfall and management of the stand.  A few bushes may die after cutting but most will reshoot to produce good quality brush ready to harvest again in about 6 – 15 years.
Brush cutters report that in some natural stands they have been cutting the same plants periodically for thirty years.  It is not known how many times broombush can re-grow from the stump after a fire or cutting or if the time of cutting (ie. season) is critical or if plant vigor is reduced after each successive cut.

Brush is normally cut by hand using a heavy knife when the broombush stems are about 1.3 – 1.7 m long.  The brush is bundled and transported to fencing contractors or brush panel manufacturers while it is still green and flexible.

The brush is cut leaving a 2 – 5 cm stump after which it is cut back using a brushcutter to encourage strong regrowth from the lignotuber after hand cutting.

Bundles must weigh 25 kg to be accepted at brush manufacturing plants.  The stems must be small (no more than 2 cm in diameter) and straight with minimal woody fruits.

 

Figure 4. Broombush stump shortly after cutting (left) and after resprouting (right) .	Figure 5. Bundles of broombush, just arrived at a panel manufacturer.

Marketing

There is a well established market existing in Australia and a 1994 study indicated that about 600,000 bundles are used in Australia every year [Sydney (130,000 bundles), Melbourne (100,000), Adelaide (100,000), Brisbane (130,000) and other (110,000)].

The continuance of this industry depends on regular and adequate supplies.  As access to the native vegetation resource diminishes, the need for commercial plantations on private land becomes necessary. There are some real opportunities for landholders looking for a long term enterprise.

Research and development supporting the industry is working on producing superior cultivators and improving production methods.

There are two major outlets for broombush.

1. Companies that buy 25 kg bundles to make into pre-fabricated panels.

2. Sell direct to fencing contractors who need 2-3 bundles to construct one metre of fencing.

Financial aspects

The economic viability of broombush is greatly affected by the following:

• cost of establishing the plantation (largely the plant cost component)
• yield
• time to harvest
• price per bundle

Further information on financial aspects and detailed economic analyses are available in the publication ‘Growing Broombush for Profit and Land Protection’ and is available through Primary Industries and Resources SA (PIRSA).

Pests and diseases to look out for

A number of pest problems have been reported in young and established plantations.

Direct seeded broombush needs close monitoring for red-legged earth-mite (RLEM) damage, prior to, and as seedlings first emerge. Spraying with insecticides at label rates can avert RLEM causing a disaster.  RLEM should not be a problem if direct seeding is conducted in spring.

Wingless grasshoppers (Phaulacridium vittatum) can be a problem particularly in newly established plantations on land that has previously been pasture.  Bare sandy soil provides ideal egg laying sites.  Wingless grasshoppers can be controlled using an appropriate insecticide or by baiting.

Sporadic defoliation of growing tips can be caused by two varieties of ‘honey beetle’.  An attack in the first year can kill some plants, but most recover without spraying and become more bushy (desirable) in the following season.

Some minor damage has been observed by the longicorn beetle, which hollows out stems.  Moth damage can be both extensive and persistent and a residual spray may be need occasionally for severe outbreaks.

Rabbits can be a real threat as the broombush makes an ideal habitat so they need to be eliminated prior to planting.

Organisations and contacts

For further information on broombush, contact the Department of Primary Industries in Victoria, or the Department of Primary Industries and Resources South Australia (PIRSA).

Industry Contacts:

Solomit Strawboards, Murtoa, Victoria.

Clive Bowman, Lameroo, S.A

References

Bulman, P., Beale, P., Knight, A. (1998) Growing broombush for profit and land protection. Primary Industries and Resources SA, Murray Bridge.
Bulmann, P., Fairlamb, J. (1994) Farm Tree Improvement Project, PIRSA (unpublished)

Acknowledgments

P. Bulman – Farm Tree Systems
C. Bowman
W. Thompson & N. Turner – Solomit Stawboards H. Showell – Ausbrush Panels & Adelaide Brush
R. Murphy – PIRSA

This Agnote was developed by Lesley Cameron , January 2003.
It was reviewed by Virginia Forrest, May 2008 and Charles Hajek, May 2009.