Alison Fleck correctly stated: "Don't confuse aggressive plants with invasive plants." Aggressive plants need permanent control; however, they stay in their own territory and do not venture out into the wild and demand space. Invasive are exotic plants of certain characteristics, which after introduction to new regions start excessive growth and spread that fill in the waterways, clog the streams and replace the native plants.
Alien invasive plants were introduced either intentionally (e.g. for ornamental use or agroforestry purposes) or accidentally (e.g. as ballast or in livestock feed). They have now become weeds in conservation areas and agricultural land, threatening the country’s biodiversity and agriculture. In addition, they can reduce runoff from water catchment areas, thus diminish the flow in streams and adversely affecting the water table.