The city council's entry by Darren Share uses plants to reflect different parts of the church building, which celebrates its 300 year anniversary in 2015.
There is a floral representation of the tower and bells cascade flowers around a wicker angel. The first of three water features showcases water running uphill along a representation of the nave. The second provides a curtain of water from one of the bells, and the third sends jets of water from the organ pipes. The display includes colours, with a focus on reds and pinks to reflect the painted windows of the cathedral.
Speaking before the prizes were awarded, Very Revd Catherine Ogle, Dean of Birmingham said: "We are very proud to be chosen for the theme of Birmingham's Chelsea display in our 300th year. It's a great way of promoting the city and raising awareness of the cathedral, its heritage and our life today."
"We're looking forward to sharing the story of 'the church that became a cathedral in the town that became a city' and continuing to work with the great staff of the Parks Department.
"Everyone will be able to see the display in Cathedral Square, later in July."