Pampas Grass

Weed Talk: By Martin Chatfield Landcare Community Weed Officer Pampas Grass( Cortaderia selloana) Pampas grass is a widespread environmental weed common in South Gippsland having been planted as an ornamental, for fodder, windbreaks and to stabilise soil. It is highly invasive , particularly in forest areas, roadsides and wetlands. It is a very aggressive coloniser, particularly on disturbed open sites. They form dense stands that exclude most other ground flora and impede overstorey recruitment. Individual flowers heads contain up to 100,000 seeds with viability exceeding 75%. Wind may disperse seed for several kilometres. Roots grow up to a depth of 3m with a spread of 4m helping established plants to tolerate extended dry spells. The large volume of dried leaf matter on and around tussocks dramatically increases fuel loads within infested areas increasing fire risk. Interestingly until the 1970s Pampas grasses in Australia consisted of low fertility strains or female plants and did not tend to have the weedy characteristics they have today, the reason they are these days during the 1970-80s large volume of seeds were imported that included higher fertility strains and male and bi-sexual plants, with the consequence that plants are know freely reproducing and spreading by seed. To control smaller plants can be dug out, all rhizome material should be removed. Where plants can not be treated immediately spread can be limited by removing emerging flower stems, cutting them at the base usually prevents them from redeveloping. Alternatively cut off maturing seed heads and placing in bags then bury or burn off site. Plants can also be sprayed with Glysophate.