David Bebarfald, who chaired the garden competition committee, said the Facebook page was the next step in their evolution because apart from a drop in entries, the competition was becoming costly to run.
"We thought there must be a better way to look at what we wanted yet still be involved in promoting gardens in the city. This represents a new direction," he said.
Gareth Carter, another of those involved in the organisation, said it was also about lifting a positive "green" image for Wanganui and getting other businesses on board.
"It can work for everyone from car yards to industries but in future, it could help generating funding to get Wanganui promoted at major events like the Ellerslie Garden Festival.
It wouldn't take a lot of businesses working together to fund a major promotion for the city," Mr Carter said.
He said Gardening Whanganui will also bring together a wide range of garden-related groups around the city and district who tended to work independently.
"Wanganui is viewed by those who live here and visit as a beautiful, safe place. The key to promoting this is sharing this message with the rest of the world," he said.
He said given the two most popular pastimes in New Zealand are walking and gardening, Wanganui was ideally placed to promote its gardens, parks and recreational opportunities.
Lisa Talbot, who's managing the Facebook page, said as well as promoting the city's gardens, it was aimed at cultivating interest in gardening.
"We've got 188 people involved so far and our goal is to get at least 500 by mid-December," Ms Talbot said.
She said people had already started to interact on the page and upload their own pictures.
As an incentive to get more people to "like" or "share" the Facebook page, anyone who joins is in line to win a $50 voucher.
