On-ground revegetation works

Before you begin

Read the guide to planning a revegetation project for advice on:

• site selection
• planting designs to meet your revegetation goals
• plant species selection.

Ground preparation

Good site preparation is the foundation of any successful revegetation project. The aim is to create soil conditions that promote strong germination, root growth, and long-term survival. This means reducing competition from weeds and improving soil structure for good root penetration.

Start preparing in spring, the year before planting. Many farm paddocks have compacted soils, nutrient build-up, and established weeds. Early preparation allows time to control these issues before planting.

Weed control before planting

Assess the competition your plants may come up against during their establishment. This can include annual weeds and perennial weeds.

Annual weeds

Common annual weeds include:

• Paterson’s curse
• Thistles and burrs
• Wild oat, rye, barley, and brome grasses

These species thrive in disturbed, nutrient-rich soils. They grow rapidly, shading out young seedlings. They can produce multiple seed crops in one season, creating a lasting seed bank

No tree, shrub or perennial groundcover seedling can effectively compete once annuals get going. They rob your seedling of access to moisture, nutrients and sunlight.

Control methods:

• Use well-timed herbicide applications or mechanical disturbance.
• Apply spray fallow techniques to create a competition-free zone.
• Use soil scalping where safe to remove weed seed banks (avoid erosion-prone sites).

Once seedlings are well established (1–2 years), their deeper roots will outcompete annuals. Promoting perennial plants helps break the annual weed cycle.

This planting site has been slashed and then sprayed with a knock-down herbicide. The preparation area is approximately 1.5 m wide. This site is ready for planting using a direct seeding machine or, with soil cultivation, can be prepared for seedlings or hand seeding. 

Another planting site spray-fallowed ready for direct seeding or soil cultivation. This particular site has been prepared for scalping. 

Scalping using a grader removes approximately 75 mm of soil including much of the soil seed bank, which is windrowed to the side. In this example, a gentle spoon drain or furrow is created that harvests rainfall from the surrounding area to the centre providing long lasting weed control and water harvesting in one action.

This high disturbance preparation method should be used very cautiously. Avoid sites prone to soil erosion such as duplex soils with a shallow sub-soil (B horizon) or sites with good native plant cover. It is best used in flat to gently sloping weedy sites with limited native groundcover.

Perennial weeds

Problem perennials include:

• Blue heliotrope
• Horehound
• St John’s wort
• Lucerne
• Paspalum and phalaris.

These species are deep-rooted and can regrow from root suckers. Cultivation alone will spread them, so control first with appropriate herbicide.

After control, use low-disturbance methods like chipping and spot spraying to manage regrowth. Over time, native understorey species will recolonise and repair the groundcover.

Soil preparation

Some sites with good native groundcover may not need soil disturbance. For most others, cultivation improves planting speed, root growth, and moisture penetration.

Some sites with good native groundcover and few problem weeds may be direct seeded without any prior disturbance of the soil. For most other sites, good soil preparation, including a deep cultivation, will:

• increase planting speed
• help seed germination
• enhance root growth and moisture penetration
• increase the survival rate of plants.

Several passes using a deep ripping tined implement will adequately prepare most soils for planting. In some cases, such as heavier soils, it may be necessary to follow this with a finer cultivation or harrow to break-up larger clods and further reduce air-pockets.

Furrows may be shaped to assist water harvesting. This can magnify rainfall by two to four times, increasing seedling survival and growth rates.

For site-specific advice on ground preparation, please talk to your Local Land Services officer. 

The ideal implement for deep soil cultivations is a 3-tine scarifier with deep ripper chaser. 

Soil cultivation should aim to fracture the soil to a depth of 30 cm and width of 0.5 m to 1 m. The scarifying tines on this grader are well positioned to achieve this. 

Aim to achieve the 30 cm cultivation depth in a minimum of two passes. Here, the grader tines are at half depth (approximately 15 cm). Working the soil down slowly avoids creating large air pockets, with the second pass achieving full depth and assisting to break up large clods. 

Final pass at full depth, producing a deep, friable planting bed suitable for seeds and seedlings. Note the scarifying bar is only approximately 0.5 m wide. Try and avoid unnecessarily wide cultivation as it will reduce the effectiveness of the water harvesting. 

This planting area has been prepared using scalping and deep cultivation of the centre line. Note the wide gap between the rows (around 10 m). Seedlings are planted close together along the rows (4 m apart) with ample space for growth available in the inter-row area. This makes efficient use of the soil preparation, minimises soil disturbance and successfully restores a woodland shelterbelt area. 

A cultivated site ready for seedling planting or seeding. Note how the grader tines have created a lip of soil on either side. This creates a basin shaped planting zone that readily holds water.

Planning for water

Water is critical for plant survival. You can improve water capture and retention by shaping the land surface.

Water harvesting techniques:

• Scalping: Remove around 75 mm of topsoil to create a shallow depression or spoon drain. This channels rainfall to plant bases. Scalping does not need to be done with a grader. On smaller sites, localised scalping can easily be formed using a spade.
• Micro-contouring: Form small basins around plants to hold runoff.
• Localised scalping: On small sites, use a spade to create planting depressions.

Water harvesting is ideal for dry and semi-arid regions but avoid it in areas prone to waterlogging.

Planting options

On-going maintenance

It is important that once you have completed your planting, you don’t just leave the new plants to fend for themselves. You need to conduct follow up inspections of your revegetated site to check:

• if seeds have germinated
• if plants are suffering from moisture stress
• that fencing remains stock proof
• that tree guards remain in place
• whether weeds or pests are impacting the growth of plants.

If you identify a problem, act quickly before the problem becomes too large to treat cost effectively.

Watering

At times, planting occurs in circumstances less than the ideal and this is where watering-in becomes very important.

Seedlings that are planted into dry(ish) soil, or during a period of warm temperatures and high evaporation rates, will need to be watered quickly. 

Tips for effective watering include:

1. Water as soon as practical after planting, preferably on the same day. Dry soil conditions will start to pull moisture from the root ball immediately after planting, causing moisture stress on the plant.
2. Water well. A litre is better than nothing, but if you are able to give the plant 10 litres or more that is preferred as the moisture will soak in deeply around the plant and last for longer. To water well you will need to create a basin to hold the water around the plant
3. Do not water regularly! Regular watering promotes weeds and shallow root growth. Try and cycle the timing of any follow-up watering with the plant’s needs (not a time table). The aim of any artificial watering should be to get the plant through a potentially tough period early in its establishment phase. Look for the early signs of moisture stress like curling or aborting growth shoots before watering.
4. Be prepared to cut your losses. Watering is expensive, mostly in terms of labour and machinery. Watering once because you planted into less than ideal conditions is good practice, watering many times through a hot dry summer can be a draining and disheartening experience.

Mulching the soil around the plant further assists with moisture retention; however, it is impractical on paddock scale projects.

If you are lucky to have native groundcover, and natural leaf litter, this will benefit your plants and reduce weed competition.

Weed management around new plantings

On-going weed control is the most important post planting management activity that you can do. Managing competitive growth within the root zone of your seedlings will substantially improve survival and growth rates.

Management methods should aim to control other plant growth within a 1 m radius of the plant. A zero tolerance of annual broadleaf and grass weeds within this zone is a good policy due to their capacity to rob moisture, nutrients and light.

The weeding methods employed (typically chipping, hand removal or shielded spot spraying) should avoid collateral damage to your seedlings. Be very careful if using herbicide sprays as accidental drift can easily occur. While it rarely causes plant death, it usually results in reduced growth for several years afterward. Accidentally sprayed parts of your plants can be immediately removed using secateurs, if practical. A good operator with an eye for detail is needed for any post planting spot spray operation.

Careful spraying around plantings can reduce weed encroachment to establishing seedlings. Tree guards left in place not only provide protection from wind or browsing animals they assist with blocking spray drift onto your seedlings. This can be maintained for several months until the seedling establishes.

Monitoring your revegetation site

You may also like to set up a simple monitoring program for your revegetated site to record things like:

• Success of preparation and planting techniques used
• survival rates of plants
• which species are growing better
• weed growth
• native groundcover
• wildlife use
• impacts (positive and negative) on adjacent crops or pastures.

These records will provide you with a good reference if you decide to undertake more planting and to help you determine if your planting is having the desired effect.