A beneficial weed can be an invasive plant that has some companion plant effect, which is edible, contributes to soil health, adds ornamental value, or is beneficial in some way. These plants are normally not domesticated. However, some invasive plants, such as dandelions, are commercially cultivated in addition to growing in the wild. Beneficial weeds include many wildflowers, as well as other weeds that are commonly removed or poisoned. Certain weeds that have obnoxious and destructive qualities have been shown to fight illness and are thus used in medicine. Reductions in abundances of weeds which act as hosts may affect associated insects and other taxa which are beneficial. For example, Parthenium hysterophorus which is native to Northern Mexico and parts of the US, has been an issue for years due to its toxicity and ability to spread rapidly. In the past few decades though research has found that Parthenium hysterophorus has been used in traditional medicine to treat inflammation, pain, fever, neurological disorders and diseases like malaria and dysentery. It is also known to create Biogas and can be used as a bioremediation agent to break down heavy metals and other pollutants.
