Hundreds of helpers dug in to ensure the Greater Manchester borough won the second-highest prize in the large city category.
Wigan was chosen to represent the region after sweeping the board at the North West in Bloom awards last year. The borough picked up a record 17 awards at the regional competition.
Wigan in Bloom champion and former deputy council leader John O’Neill said: "Volunteers have made a real difference by working with the council planting thousands of new trees and flowers, creating public art, producing eco-projects.
"As the bid has been community led, it has proved a cost-effective and hugely valuable way of improving environments, getting people outdoors and encouraging community cohesion.
"Media interest in the competition has already given Wigan Borough coverage in the national and regional press, showcasing the attraction of the borough to potential investors."
Council member for the environment Kevin Anderson said: "Just to get to the finals and represent the north-west is spectacular; to come away with this prize is fantastic. In Bloom has been great to showcase the borough in a different light.
"This has been a community project from the start and the award is a tribute to the many schools, residents’ groups and individuals who have worked so hard to make Wigan borough bloom."
Community projects include allotments at St. Peter’s Church of England Primary School in Hindley and the work of the Friends of Hindley Station.