Heading the record field of 20 show gardens, his Reinforcing Nature garden used woven steel rebar curving through water, soil and timber to create a refuge at its centre.
Benge, a director at Watergems, said he did not know of anyone else using rebar metal in gardens. The idea came from a British Association of Landscape Industries grand award-winning garden in 2009 that needed rebar for retaining walls.
Watergems, which often works on council and commercial wetlands and lakes, sees lots of opportunities for using rebar in gardens.
But Benge pointed out water was harder to use than the metal. "You get algae and blanketweed problems with water. It's actually difficult to deal with. At flower shows the garden is only there for a few days so there's not time to bloom," he added.
"Temporary water gardens are easy. They're harder long term. They're not straightforward. They have to form the basis of design and not be an add-on later. We don't pretend you can build in two days. You need to know about things like chemistry and biology."