The sea of white lilies carpeting the forest floor south of Margaret River is a picturesque view, but an ugly sight for conservationists.
The arum lily, considered one of the most damaging weeds in the country, was banned from sale in WA more than 20 years ago, but the rogue garden plant's infestation of forests across WA's South West shows no sign of slowing.
Arum lilies in Boranup Forest, south of Margaret River. (ABC News: Georgia Loney)
More than 3,000 private landowners have requested help to eradicate the weed on their properties.
But there are questions over the WA government's willingness to do the same in the state's national parks.
Forests under threat
In Boranup Forest, 300km south of Perth, Obelia Walker has mapped an enormous arum infestation through her work for Nature Conservation Margaret River.
Arum lilies are a major issue in sections of the Boranup forest. (ABC News: Georgia Loney)
The organisation is co-ordinating a three-year blitz helping private landholders control the spread of lilies on their properties, funded by the WA government.
Those efforts have been successful, but she is worried about the infestation on public land.
Obelia Walker says arum lilies are causing problems in native forest, but key areas are being protected. (ABC News: Georgia Loney)
"If you think about where the majority of diversity happens in the forest, it's in the understorey," she said.
"The way the arum lily behaves when it gets out of control like this is it's just smothering the understorey, out-competing native plants and destroying habitat for wildlife as well."
The arum lily is worsening in the Tuart Forest National Park, near Busselton, conservationists say. (ABC News: Georgia Loney)
Further north, in the Ludlow Tuart Forest near Busselton, local volunteer Des Donnelly has petitioned the Cook government to do more about the national park infestation.
"It's probably worse than it ever was," he said.
"If we don't manage them, we can probably kiss [the forest] goodbye in the next 50 years."
Mr Donnelly was behind a petition presented to state parliament earlier this year, calling for government agencies to do more to fight the flower in the forest
Arum lilies on the roadside in Tuart National Park near Busselton. (ABC News: Georgia Loney)
"It's a token effort if you like; Main Roads do a little bit, DBCA do what they can do with their small budget," he said.
"Generally, we're only just fiddling around the edges."
Glen Taylor's beef farm sits opposite the Boranup National Park, where there is a large infestation.
Glen Taylor says arum lilies are infesting the forest neighbouring his property. (ABC News: Georgia Loney)
He has managed to all but eradicate the lily from his own land, but it still encroaches at the borders.
"That is where it's a struggle," he said.
"It's a difficult thing to educate people how much damage they are doing to the natural environment."
March of the arum continues
The state government's focus is on controlling arum lily in priority areas, rather than trying to eradicate the plant, prompting criticism from conservationists.
But a state government spokesperson said eradication was not realistic, with more than $2.6 million granted to arum lily control programs across the South West over the past nine years.
Arum lilies can be seen throughout the Ludlow Tuart National Park. (ABC News: Georgia Loney)
"While arum lily can be managed, it is not currently considered feasible to completely eradicate the species from the landscape due to its extensive distribution and ability to regenerate and spread," the spokesperson said.
The spokesperson said it had undertaken control across areas in the Tuart Forest National Park, Leeuwin-Naturaliste National Park, Wooditjup National Park, Yelverton National Park, and selected state forest and nature reserve sites.
Creative solutions required
Conservationists agreed that the National Biosecurity Committee's inclusion of the arum lily on its list of Nationally Established Weed Priorities could lead to more innovative methods of control.
Nature Conservation's Obelia Walker hoped it would unlock funding for research into more cutting-edge methods to tackle the weed.
"We can't spray out way out of this problem,"
she said.
"It might be something quite novel; it might be a fungus or a disease, but it's an exciting space."
Arum lilies are infesting the Boranup forest. (ABC News: Georgia Loney)
Invasive Species Council policy director Carol Booth said the war on the lily was ultimately reliant on political will.
"I mean, the arum lily is one of the classic examples in Australia of a garden plant that's just gone rogue," she said.
"Which of these weeds are our state and federal governments prepared to put funding into to generate a much more collaborative and concerted approach to managing their risks?"