Management of Invasive Alien Plants

Any control programme for alien vegetation must include the following 3 phases:

• Initial control: drastic reduction of existing population.
• Follow-up control: control of seedlings, root suckers and coppice growth.
• Maintenance control: sustain low alien plant numbers with annual control.

Mechanical & chemical methods

Where trees cannot be utilised (on steep slopes), do not fell trees, control them in situ. Select from the following options:

Basal bark

Application of suitable herbicide in diesel can be carried out to the bottom 250mm of the stem. Applications should be by means of a low pressure, coarse droplet spray from a narrow angle solid cone nozzle.

Hand pull

Grip the young plant low down and pull out by hand (using gloves).

Ring-barking (girdling)

Bark must be removed from the bottom of the stem to a height of 0.75-1.0 m. All bark must be removed to below ground level for good results. Where clean debarking is not possible due to crevices in the stem or where exposed roots are present, a combination of bark removal and basal stem treatments should be carried out. Bush knives or hatchets should be used for debarking.

Frilling

Using an axe or bush knife, make angled cuts downward into the cambium layer through the bark in a ring. Ensure to effect the cuts around the entire stem and apply herbicide into the cuts.

Where trees can be felled and removed, use chainsaws, bowsaws, brushcutters or cane knives.

Cut stump treatment

Stems should be cut as low as practical, as stipulated on the label. Herbicides are applied in diesel or water as recommended for the herbicide. Applications in diesel should be to the whole stump and exposed roots and in water to the cut area as recommended on the label.

Stem injection

Punch downward slanting holes into the main stem using a sharpened metal spike. Space holes around entire circumference of lower stems. Inject the herbicide directly into the plant – ensuring to inject around the stem. Follow label recommendations – for invasive cactus species.

For more information on the management of invasive alien plants, please contact us.