Grow weeds, make millionsARCO IMAGES GMBH/ALAMY St John's wort (Hypericum perforatum). Weeds are a pain for most gardeners, but certain herbs that could be medicinal heroes actually grow as weeds in New Zealand. St John's wort, revered as a medicinal plant throughout history, also has weedy status here and the St John's wort beetle is used for biocontrol. Without eradication efforts, St John's wort would grow about four plants to one square foot. It is also interesting to note that St John's wort does very well in dry conditions."

Source: Stuff October 30, 2017 00:33 UTC