In most situations, fertiliser is not necessary and can be expensive. However, less fertile or highly eroded sites may benefit, increasing growth in the first few months. Use only slow release fertilisers that are designed for native, for example, the NPK pill.
Avoid concentrated fertilisers such as superphosphate and animal manure as the high nutrient level can burn the seedlings. Do not use phosphorous fertilisers near Banksias or Dryandra species. In a new area apply it to only some plants to see if it improves growth.
It is essential to ensure good weed control if you fertilise. Failure to do this will mean greatly increased competition from weeds. In all cases, fertiliser should not come in direct contact with the tree stem. Gypsum may improve the structure of heavy, dispersive clay soils which set hard when dry. Application rates of 500 gams per square metre are frequently used. Gypsum may be broadcast or applied manually.
It is vital to water at planting time, even if the soil is moist. One litre of water (or more) poured slowly around the planted seedling helps overcome transplanting shock and removes air pockets.
Where annual rainfall exceeds 450 mm, no further watering should be needed or given, provided the site has been ripped, weed control is good and the appropriate species have been planted at the right time. However, it is always wise to check the seedlings at regular intervals over the months following planting to ensure that the seedlings are surviving.
In drier areas, or when the following summer is hot and dry, seedlings may benefit from one or more waterings over summer. A litre per seedlings should be sufficient. However, watering should be limited to once a month at most, so as not to weaken the seedlings.
A thick mulch of old straw, rice hulls, gravel, carpet, newspapers, grass or leaf mould, reusable plastic sheets or pre-cut squares of weed-mat placed around the young plants helps conserve moisture and suppress weed growth. Ensure to keep the mulch clear of the plant stem as contact can cause collar rot.
However, some tree planters report that mice and insects can colonise the area under the mulch and damage the roots, so keep an eye out for any problems.
If using newspaper for mulch, scalp site first to form a dish for water to collect, to guard against water running off the paper and away from the plant.
Guarding and staking
Placing tree guards around your seedling is critical in enhancing the survival rate of your seedlings. They are instrumental in preventing rabbits and hares from eating the tasty new seedling shoots, protect the seedlings from winds and help maintain a warm and moist environment around the seedlings.
In many areas, the failure to place tree guards result in a high loss of seedlings. While it is an additional expense, the increased survival rate is worth it.
Tree guards come in various sizes, with differing costs involved. The most economical guards are milk cartons, which are held in by two bamboo stakes. These are more suitable for areas with the softer loamyor sandy soils; the bamboo stakes are difficult to get in to hard, clay soils.
Another common tree guard is the plastic sleeve, which is held in by three hard wood stakes. While these are more expensive, they are larger and therefore afford a greater level of protection, they allow more light through to the seedlings and are more suitable for harder ground as the stakes can be hammered in.
However, plastic guards should not be used near waterways, as the guards can easily get in to the waterway, damaging water flow and posing a risk to fish and wildlife.
Plastic tree guards should be removed after the seedlings are healthy and well established – usually after 3-4 years, to prevent the plastic from blowing away an causing a litter problem.. Milk cartons may not need to be removed as they are biodegradable; however they still can cause a litter problem, so keep an eye on them.
Where wallabies are a problem, tall and sturdy tree guards may be necessary. There is now a range of wire and plastic guards available for differing conditions. Seek out advice for what is the most successful in your area.
Even in wet or windy situations it is usually unnecessary to stake seedlings. Generally, staking results in weak lateral root development, as the seedlings do not need to build up their own strength against the wind. Staking may be necessary where advanced trees are used.
Protecting your trees
The best step to successful tree protection is to ensure that an effective ongoing rabbit and hare control program is in place. Rabbit control techniques include harbour destruction, poisoning, fumigation and fencing. For further advice on these control methods contact your local DSE office or landcare group.
Many species (eg Casuarina, Eucalypts) are attractive to hares and rabbits and in some areas cockatoos/corellas will pull out unguarded seedlings within hours of planting. Potential damage from rabbits and hares should never be underestimated and in some areas netting may be required. Alternatively some farmers report success with old tyres around the seedlings in deterring these pests.
Severe infestations of sawfly larvae, autumn gum-moth caterpillar or leaf skeletonisers can be controlled by manual removal or spraying with contact insecticide. A low toxic spray to control scale insects is white oil and a wetting agent – always follow the manufacturer’s directions. Wingless grasshoppers may be sprayed with an appropriate contact insecticide or baited with bran sprayed with an appropriate contact insecticide as per the manufacturer’s instructions.
Some species, including Eucalyptus globulus (Blue gum), Eucalyptus tereticornis (Forest red gum) and Eucalyptus camaldulensis (Red gum) are tolerant of occasional defoliation, which may avoid trees blowing over in early spring. Local species of acacias, banksias and bursaria aid long term control of insects by attracting insect eating birds, wasps and mammals. You may find this will also reduce insect attacks on your crops.
In most plantings there will be some loss of seedlings – up to 20% is not unusual. Some replacement of dead or poor performing trees may therefore be needed. It is always important to record the success of various species and methods of planting for future reference.
And most importantly, talk to other tree growers in your area and listen to their advice and experience. Have a look around your local area and observe the results already obtained.