English ivy, a garden plant that has escaped into the unique mountain environment, has spread to the size of a city block killing native growth at the base of the mountain.

Environmentalist Robert Alford said the plant had spread ferociously in the past few months after Orange’s record winter rainfall created an intense growing season.

Mr Alford has brought together an ivy league of environmentalists, bike riders and National Parks and Wildlife Services to try to cut out the plant.

He is also asking the public to attend a first working bee at 9am on Sunday, February 19, from the Mountain Tea House.

“English ivy has gone wild. It has just taken off,” he said.

“Under the guidance of the National Parks we want to get in at ground level. We want to cut a section of the ivy out so it can’t grow.”

Mr Alford said the ivy was not a noxious weed but was doing plenty of damage to the mountain’s native plants over “the size of a city block”.

“It’s a leaf. It’s feral to native bush. It grows and it strangles everything.

“What the public is seeing is just the tip of the iceberg.”

He said the groups were united in the push to clean out the invading ivy.

“We’re basically putting a common goal there so everyone can come together for a common goal. We’ve got to start bringing people together rather than taking sides.

“It’s good for tourism, it’s good for the environment.”

Environmentally Concerned Citizens of Orange president Nick King said that while the issue of opening mountain bike trails on Mount Canobolas was not resolved the groups wanted to fight the ivy.

“English ivy was probably introduced into Australia as a garden plant. It has escaped and is now recognised as a serious environmental weed in several states, including NSW,” he said.

“It is an aggressive invader that covers and kills trees. As a ground cover it chokes all other competing plants, ultimately forming an ivy desert where nothing else will grow.

“Such ivy deserts currently exist in many parts of the Mount Canobolas State Conservation Area, particularly at the foot of the mountain.

“It is in recognition of this threat that an alliance has been formed between the NSW National Parks and Wildlife Service and the Orange Mountain Bike Club, Environmentally Concerned Citizens of Orange and the Orange Field Naturalist and Conservation Society.

“The aim of this group is to provide support for the National Parks' existing program to control the ivy infestation,” he said.

Mountain bike enthusiast Rod Farrell said riders were concerned about the environment and wanted to help rid Mount Canobolas of the ivy.

“Mountain bike riders do more than just ride bikes,” Mr Farrell said.