The first Royal Horticultural Society garden in an urban area has welcomed its first visitors, completing what the charity has billed as Europe's "biggest hands-on horticultural project".
The 154-acre RHS Garden Bridgewater in Salford has opened a year later than planned, due to the Covid-19 pandemic.
RHS Director General Sue Biggs said the £35m garden was "the result of years of hard work".
The charity said it was hoped a million people would visit the site annually.
A spokesman said the project, which has seen about 250,000 new plants put into the site, had created more than 100 jobs, half of which were filled by locals living within five miles of the garden.
He added that it was hoped the garden would generate about £13.2m a year by 2030.
The charity said the Bridgewater team had also begun a pioneering programme that "recognises the connection between gardening and better health".
It will see local doctors refer patients to the site through "social prescribing", where they can become involved in a scheme that uses therapeutic gardening, gardens and green spaces to help them.
RHS Therapeutic Gardener Ozichi Brewster said 30 people had signed up so far.
"The people who've been referred to us regularly see their GP or have A&E appointments for chronic conditions that can flare up," she said.
She said while gardening "can be seen as hard work", doing things like "weeding and picking 'deadheads' off a plant can be very therapeutic".
"The person is engaging with nature and out in fresh air," she said.
"There's not a lot of thinking going on. It's very mindful and they're immersed in it.
"Things drop away, we're heavy thinkers in today's world, but it allows you to leave things behind."
The garden's curator Marcus Chilton-Jones added that the garden had the aim of being closely connected to the surrounding area.
"Rather than us putting up a fence and inviting people to come in, pay a fee and have a cup of tea... it's much more than that," he said.
"There are links between us and the community outreach team, which goes out and takes horticulture to the community, but we're also inviting people in to work on site as well.
"So there's a very two-way street and a symbiotic relationship that doesn't just have a fence around the outside."
Malkiat Singh, who has volunteered to help in the garden through a local support group, said he was "loving every minute" of being involved.
"I love it. I'll be coming here every week and helping out," he added.
The garden has been built on the former grounds of Worsley New Hall, the estate once owned by the Earl of Ellesmere which was itself home to "glorious, formal landscaped gardens", the charity said.
However, during the early 20th Century, the hall fell into disrepair and following a fire in 1943 it was finally demolished by a scrap merchant, who had bought it for just £2,500.
In subsequent years parts of the grounds have been used as a garden centre, a Scout camp and a rifle range.
Ms Biggs said the RHS and its partners, Salford City Council and Peel Group, were thrilled to be able to celebrate the "monumental achievement" of bringing the area back to life.
Visitors will be able to discover a host of gardens, including the 11-acre Weston Walled Garden - believed to be the largest publicly accessible working walled garden in the UK - and the Paradise Garden, which will showcase exotic planting inspired by Asiatic and Mediterranean gardens.
Salford City Council's Chief Executive Tom Stannard said the authority's £19m investment had "played a pivotal role in making the garden a reality".
"For every single pound we invest in this, we will see several pounds come back into our city," he said.
The garden is the RHS's fifth garden and will sit alongside its sites at Harlow Carr in North Yorkshire, Hyde Hall in Essex, Wisley in Surrey and Rosemoor in Devon.