Currently (late May) there are abundant yellow flowers growing up the steep slopes where banana plantations at Korora and other places along the Coffs Coast.
This intrigued me when we first moved up here to Coffs Harbour – just what were these plants?
This question led me to ask the Coffs Harbour Landcare group about these plants.
The Japanese Sunflower Tithonia diversifolia has its origins in Mexico and Central America. Despite its common name, this species is not native to Japan. With sunflower-like flower heads which are up to 10cm across and orange-yellow petals 4-5cm long. The seeds are hairy with a ring of scales and two spines.
This plant is a weed and is considered an environmental weed on the Coffs Coast and can be dug out or chipped, where infestations are small. Otherwise it is recommended to spray with metsulfuron-methyl at 1g/10L with surfactant.
The flip side:
Even though the Japanese Sunflower is a weed that grows quickly, it has shown great potential in raising soil fertility in soils which are depleted in nutrients (nitrogen, phosphorus and potassium).