[The Northern Star July 13, 2011] -- A LARGE infestation of one of Australia’s worst weeds has been found near Kyogle. A community member reported the infestation of hymenachne during a recent Far North Coast Weeds field day, at Lismore. Noxious weeds officer Rhett Patrick said that during the 1980s Hymenachne amplexicaulis was promoted as a ponded pastoral grass in NSW and a couple of Far North Coast land owners planted it. “It is now listed as a Weed of National Significance,” Mr Patrick said. “Hymenachne is a highly aggressive invader of waterways, riparian areas and drainage channels. It spreads by vegetative fragments and seed. Each flower on a hymenachne plant is capable of producing more than 4000 seeds. Hymenachne forms dense mats which choke waterways and water storage areas and block drainage channels. It readily degrades water quality and displaces native wildlife and other vegetation. Livestock have been known to walk out on to large mats of hymenachne, fall through, get tangled up and drown. Large mats can also be picked up during floods and tear down fences and damage other infrastructure.” Mr Patrick said hymenachne control was not easy. It was resistant to herbicide treatment and it often grew in swampy, wet areas, which were inaccessible with control equipment. Far North Coast Weeds and the Northern Rivers Catchment Management Authority had obtained a Caring for Our Country grant to help combat the weed. The grant helped Far North Coast Weeds install five hymenachne warning signs at high-risk locations around the region. The grant also helped fund several field days, held across the Richmond River catchment and to help manage hymenachne in the catchment. The organisation had so far identified 19 properties with infestations of hymenachne covering a total area of more than 45 hectares. Regular control work on all the sites had brought eight properties close to full eradication, while the other 11 properties were being managed effectively.
Anyone spotting hymenachne should call 6623 3833 or go to www.fncw.nsw.gov.au.
