Feature Weed

Parrot's Feather

(Myriophyllum aquaticum)

Myriophyllum aquaticum, commonly used in ponds and aquatic gardens, is a bright green perennial fresh water herb which can grow on the banks of waterways or can rise up a few metres through water. The leaves have a feathery appearance, which occur in whorls of 4 to 6, with stems reaching 5m in length. All plants in Australia have female flowers which are small and white/transparent making the only means of reproduction vegetative.

The stems of the Parrot’s feather creep and root at its nodes near the base of the plant, making this highly competitive plant capable of rapid growth and spread in freshwater systems. It can form dense mats, which completely excludes native plants and its high tannin content means that fish tend not to eat it. Dense infestations affect recreational activities such as boating, fishing and swimming. Free-floating mats can interfere with water supplies, irrigation systems and other infrastructure and it can impede water flow.

Methods of control include mechanical removal, though much care is needed when handling this weed due to its ability to reproduce from broken stem segments.. Chemical control includes Glyphosate at 100ml/10L of water and Reglone® at a rate of 40mL/10L of water, both need to be used when the plant is actively growing and more than 25% is above the water.

Please note: when using any agricultural chemicals ensure that you always follow instructions on the label and any permit. Users of agricultural chemical products must always strictly comply with the directions on the label and the conditions of any permit. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website.

 

Parrot's Feather

Above: Parrot's Feather (Myriophyllum aquaticum)