Backers of an arboretum at Fort Williams will begin trying to raise nearly $80,000 to complete Phase 1 of the project by the spring.

Voting Nov. 18, the Scarborough Planning Board unanimously approved a proposal for an arboretum at the park that will replace invasive plant species such as bittersweet plants with native plants such as witch hazel and dogwoods.

The group doesn’t know what fundraisers it will do, but plans to work with businesses and private donors that have shown interest in the project, said Kathryn Bacastow, one of the group’s members.

“We’re going to try and be creative,” she said. “We have friends of the project that have experience in fundraising.”

She said a woman who lives in Australia whose father was stationed at Fort Williams during World War II has expressed interest in donating money.

The Fort Williams Advisory Committee has endorsed the citizens’ project and will work to raise money for the arboretum through a series of private fundraisers.

The citizens’ group that proposed the arboretum will not break ground on the project until the money is raised, said John Mitchell, one of the group’s members who also designed the blueprint for the arboretum.

Phase I, which will focus on the area of Batter Hobart, adjacent to the cliff walk trail, is expected to begin in spring.

The group has about 15 more areas that it wants to develop, but there isn’t a timeline for those phases, Mitchell said.

“One of the goals is to go into areas that are just being overtaken by invasive exotic plants that essentially choke the trees,” he said. “They have also blocked off many views of Casco Bay.”

The arboretum will feature walking trails to the cliff walk and new landscaping. The project also includes replacing trees that have been choked off by vines of the bittersweet plants.

“It’s really a mess,” said Kristine Murray, a member of the citizens’ group. “There are a lot of aging trees, and we’ve lost quite a few of the 100-plus-year-old oaks. We want to replace those and remove the bittersweet and poison ivy from the area.”

Several native species of plants will be sown to enhance the park’s appearance and keep the oak trees safe, said Bob Malley, Cape’s public works director.

Cape Elizabeth in 2004 conducted an arborculture study – a study of how trees grow and respond to cultural practices and the environment – and discovered the destruction the foreign plants were causing, Malley said.

The citizens’ group and the Fort Williams Advisory Committee will maintain the arboretum, Malley said.

The arboretum also has educational potential, he said.

“The area could also be utilized for outside classrooms and explain the different plants and what they are and why they are there,” he said.