Apply as a foliar spot spray to completely wet all leaves and stems. Coverage should be to the point of run-off in that the chemical mix is just beginning to drip from the leaves once the spraying is completed. Think of painting a wall and use that motion in your spray action to achieve full coverage of the foliage, then use a more directed stream to thoroughly treat the stems and canes.
This type of application is called high volume spraying as you are applying a large amount of spray mixture to the target weeds. Provided that good coverage of the target weed is possible, high volume spraying can be completed using a variety of equipment – from a small hand pump unit to a knapsack sprayer through to a large motorised pump and hand gun unit.
With a foliar spray you are looking to capture enough chemical on the foliage to kill not only the above-ground portion of the weed but all of the root mass as well, so good coverage is essential. If you are spraying very large weeds like blackberries that are several years old, ensure that canes on the inside as well as the outside of the foliage mass receive direct contact with the applied spray.
As a guide, one hectare of blackberries 1–2 metres in height will typically require a spray volume of 3000–4000 litres to be thoroughly covered, whilst the same area of a small herbaceous weed such as ragwort will require 500–1000 litres.
A video demonstrating the correct techniques for high volume spraying can be accessed here.
Equipment Required for Application
- Depending on the size of the job at hand:
- Large dense infestations (for example large old dense blackberry stands) are best treated with a large motorised pump and hand gun unit. This equipment can often be hired or a contract spray applicator can be engaged.
- However, a suitable knapsack or hand pump spray unit will suffice in many situations, provided that good coverage can be achieved (to the point of run-off).
- Ideally use a spray unit that is dedicated for application of herbicides only (to avoid cross contamination).
- Measuring jug.
- Cotton overalls or long-sleeved shirt and long pants.
- Washable hat.
- Elbow-length nitrile/neoprene gloves.
Application Timing for Best Results
In general, smaller weeds are easier to control than large ones.
Garlon 600 is most effective when applied to weeds that are not stressed due to lack of moisture, excessive heat, insect damage, etc. and are actively growing. Actively growing weeds will draw the chemical into the vascular system and transport it through the stems and down to the roots to ensure maximum efficacy.
A general guide to the best time of the year to treat common woody weeds can be found in this table.
Garlon 600 needs to penetrate into the leaves of treated weeds before any rainfall occurs so do not make applications if rain is possible before the spray is completely dry – usually one hour. Similarly, avoid application if the leaves are wet from rainfall or dew.
Once the weeds have been sprayed, leave them undisturbed so that the chemical is able to move throughout the leaves, stems and roots and provide complete kill. Disturbing the weeds by slashing, burning, mulching, etc. before the chemical is fully distributed will compromise the control achieved. We recommend that blackberries and other woody weeds not be disturbed for six months after spraying to maximise the performance of Garlon 600.
For most weeds the rate of Garlon 600 to apply is between 170 and 340 mL per 100 litres of water.
Always check the label for the correct rate. A copy of the label can be accessed here.
Correct Mixing Procedure
If possible, mix Garlon 600 with clean water sourced from town supply or a rain water tank, although any source of clean water may be used. Avoid using water that is particularly ‘hard’ or strongly alkaline as that may reduce herbicide efficacy. Half fill the spray tank with water then add the Garlon 600 before adding the remainder of the water. If the product label requires the addition of a spray oil, penetrant or wetting agent to assist in control your particular weed population, mix in once the spray tank is full.
Once mixed, the spray solution should ideally be kept agitated and used immediately. However, if circumstances conspire to interrupt spraying, a mixture of Garlon 600 and water can be stored for up to seven days, provided that it is intermittently agitated each day, and well agitated again before use.