When Trees and Shrubs are Weeds 

Weedy trees and shrubs choke gardens, invade waste areas, forests, waterways, wetlands, and natural habitats. They are often early colonisers and change natural ecosystems by shading out native plants and altering soil conditions.

Control

Many weedy trees and shrubs are too large and too well established to spray effectively and most weedy shrubs and trees will re-sprout if you simply cut them down.

First identify what the weedy shrub or tree is and choose a control method depending on the size of the infestation, and how persistent the species is.

Several methods can be used to control weedy trees and shrubs:

• Cutting and Painting - Cutting and treating stumps is the most effective method to use for most situations, particularly with smaller trees and shrubs and those that are likely to re-sprout from the base (such as elderberry and Darwin’s barberry). This method minimises the use of herbicide in the environment while being very effective.

1. Cut the trunk of the plant close to the ground with a straight flat cut. The cut should be horizontal so that the herbicide sits on the cut area.
2. Immediately apply a thick layer of Weed Weapon Invade Gel or Stump Stop to the cut stump. For best results paint the stump cut within 30 seconds of cutting.

• Spraying – If the trees or shrubs are small you may be able to spray them completely with Weed Weapon Extra Strength plus Dye & Stick. For best results apply in warm sunny conditions when the tree or shrub is growing actively.

• Manual Removal - Hand pulling can be used for smaller plants. Try not to disturb the soil more than is necessary or new weed seeds will germinate.
• Ringbarking - Ringbarking has limited effectiveness because many trees and shrubs can re-sprout from the base. Sycamore and others can heal the wound in their bark.
  
  • Use a sharp blade, chisel, axe or saw to make two deep parallel cuts all way around the base of the tree. Make the cuts through the bark and into the sapwood at least 5 cm apart.
  • Remove all the bark between the cuts.
  • Follow up 6 months later to check the stump has not re-sprouted or the bark healed.

David Brittain
Kiwicare