Like proud parents, Ann and Bruce McGregor – unpaid workers in the area for 39 years – show off the green vistas they have helped create from numerous weekend tree plantings, weed removals and planning meetings.

However, it's the details that they cherish. In a curve of the creek north of Blyth Street, Brunswick East, they point to wattlebirds picking insects from the limbs of the 20-metre red gums planted as seedlings in 1985.

Nearby, in the creek, they spot moorhens which graze among the reeds that have sprung up.

Walking along a dirt trail next to the river, the McGregors point out the native wattles, saltbush and poa tussock that have replaced the exotic willow trees, fennel and boxthorn of early European settlement.

Dr McGregor was recently pleased to see Muslim women walking along the path. It runs over 20 kilometres from Clifton Hill to Campbellfield.

He said the aim was "getting the community to come down and use the place, for recreation and a brush with nature".

When the McGregors moved to Brunswick in 1976, the Merri had no path and visitors almost needed a machete to get through the weeds.

Locals dumped household garbage, sheep innards left over from barbecues, tyres and cars in the creek.

In 1976, where there is now a popular park between Kirkdale and Victoria streets, was a tip for Whelan the Wrecker, and across the creek was a concrete Board of Works depot. It is now also a large park.

In 1976, the McGregors helped found the Brunswick Merri Creek Action Group, partly to lobby against state government plans to turn the Merri corridor into a freeway.

The group, in turn, was part of the Merri Creek Co-Ordinating Committee, which united many councils and community groups to build the path, replant native vegetation and (successfully) lobby politicians to scrap the freeway.

A further fight came in 1997, when the Craigieburn bypass of the Hume Highway was earmarked to cross Merri Creek six times, threatening native grass and frog and moth species. After community outcry, the bypass was moved east, with only one creek crossing.

The McGregors, who are keen Friends of Merri Creek members, are set on protecting the Merri in urban growth areas such as Wallan, where there are old red gums and rare native lilies and skinks.

The exhibition, Merri Creek: From Wasteland to Parklands, will be launched at Brunswick Library at 10.30am on Tuesday. It is on until October 30, before moving to other Merri Creek municipalities. The McGregors will give a talk at Brunswick Library at 7.45pm on October 15.

For further information, see the Merri Creek Management Committee website.