This method involves mixing an oil-soluble herbicide in diesel and spraying the full circumference of the trunk or stem of the plant. Basal bark spraying is suitable for thin-barked woody weeds and undesirable trees.
Basal bark spraying is also an effective way to treat saplings, regrowth and multi-stemmed shrubs and trees. This method allows the herbicide to enter underground storage organs and slowly kill the targeted weed.
The entire circumference of the stem or trunk should be sprayed or painted with herbicide solution from ground level to a height of 30 cm. It is important to saturate the full circumference of the trunk, and to treat every stem or trunk arising from the ground.
Basal bark spraying is a very effective control method, and is a good way to tackle inaccessible areas such as steep banks. This method will usually kill difficult-to-kill weeds at any time of the year, as long as the bark is not wet or too thick for the diesel to penetrate. The work is often best performed by contractors.