Eradicating aliens: poison or pull them out?
Vigorous regrowth of invasive alien plants, following a fire (such as the Knysna example), leaves landowners and land managers with the daunting task of dealing with a major problem.
Landowners in favour of hand-pulling weeds argue that when applying herbicide, much damage is done to indigenous regrowth, which will also perish as a result of the indiscriminate use of herbicide.
There is also a significant number of landowners who feel that herbicides are detrimental to a healthy natural environment, which ultimately will cascade down to human and animal wellbeing in contaminated water and food. Exposing seedbed
Others argue that, by hand-pulling weeds, the underlying seedbed becomes exposed, allowing many new seedlings exposure to sunlight, triggering renewed and immediate regrowth.
Also, by hand-pulling larger plants, chances are that the (unintended) effect, by ripping deep and extended root systems from the soil, may trigger erosion on steep slopes, leading to further land degradation.
Ultimately, the scale and nature of the regrowth problem and, perhaps more importantly, the associated cost in dealing with the matter, become the deciding factors. Cost a serious factor
When dealing with several hectares subject to invasive alien regrowth, cost to company becomes a serious factor.
Hand-pulling of weeds on any scale is labour intensive and therefore costly, and the window to apply hand-pulling is small in comparison to the invasive alien plant rate of regrowth.
Costs associated with dealing with mature and semi-mature invasive alien plants, compared to young (below knee height) plants, holds an exponential cost increase in eradication efforts.
Where hand-pulling of weeds (especially at an early stage, and on a manageable piece of land may be an option to landowners, when dealing with large-scale invasion, herbicide application becomes a viable and preferable option.
Registered herbicides, when applied responsibly and according to specifications, hold little negative implications for the environment. More information
SCLI is a public platform for landowners and land managers with an interest in the control and eradication of invasive alien plants. More info: www.scli.org.za
Port Jackson showing signs of deterioration after initial herbicide application.
Hand-pulling of rooikrans on steep slopes on the Western Heads (Knysna).