The Southern Highlands Botanic Gardens officially opened and Mary Poppins landed in a permanent position at Glebe Park.

More than 300 people witnessed the official opening of the first stage of the gardens, which had been about 20 years in the planning stages.

It was the final official event in a year-long sesquicentenary celebration for Moss Vale and Bowral.

NSW Governor Marie Bashir sung the praises of hard working and dedicated volunteers at the garden opening.

She said it was a joy to attend the event in what she described as one of the most beautiful places on the continent... "an area renowned for the beauty of its gardens".

In fact, creation of the Botanic Gardens is something that the governor has been closely associated with, having attended the official launch three years ago where she planted a tree on the Foundation Walk established within the 15 hectare site on the corner of Old South and Kangaloon Road, Bowral.

Wingecarribee Mayor Juliet Arkwright described the gardens as an "oasis for guests to enjoy for generations".

"This is our legacy, this is our future, this is for our children for years to come," she said.

Southern Highlands Botanic Gardens chairman Charlotte Webb paid tribute to the many volunteers and people who had donated or sponsored the project to reality.

She said it was the work of everyday people who had planted and prepared the site for the official opening of what would be a community space for all to enjoy.

In the afternoon Glebe Park was a sea of umbrellas while the two-metre tall bronze statue of Mary Poppins - that was once to stand in New York Central Park - was unveiled in front of hundreds.

Bowral resident Paul McShane and his daughter Melissa set up the Mary Poppins Birthplace Campaign in 2009, which helped to raise almost $100,000 to build the monument.

Mr McShane said the sculpture was a gift to the Highlands community and it told a story of great inspiration and accomplishment.

"It's better than we could have wished for," he said.

Miss McShane said the statue was a good visual way of recognising that Travers was here and Bowral played a significant part in her life.

"This project has been ten years in the making. It's still not a widely known fact that Bowral is Mary Poppins' birthplace but this statue should change that" she said.

Inspiration for the life-sized sculpture came from a sketch by British Sculptor, Sean Crampton (now deceased) and his daughter Harriet and granddaughter Rose Treadwell flew over from New Zealand to see the sculpture erected.

"It's beautiful and it's a real privilege to be here and see this finally come to fruition," Harriet said.

NSW Governor Marie Bashir said it was fitting that the statue was erected just a few hundred yards from where Travers grew up.

Chairman of the committee Terry Oakes-Ash said the project brought the community together.

"It's been 100 years since Travers lived here, so it's fitting that the statue gets erected this particular year."