Ellerslie International Flower Show, which takes place on 10-14 March, is considered the equivalent of the RHS Chelsea Flower Show in New Zealand, with over 100 exhibitors and 30 gardens.
Stretching 12m across the shore of Victoria Lake, Chris Beardshaw's English landscape garden will extend 64m into the Hagley Park showground.
It will feature almost 10,000 plants, including 4,500 annuals and 3,000 herbaceous plants.
Beardshaw said: "This show has a great reputation internationally. Our garden is not only the show's largest ever exhibit but it is the largest show garden I have ever created too."
The garden will be positioned between two large poplar trees on the shore of Victoria Lake, borrowing from the surrounding landscape to make the garden look like it goes on endlessly.
He added: "The borders are 3.6m wide, punctured with trees and shrubs so as you look towards the lake there will be a kind of rhythm in the way the structure unfolds. Underneath will be a swathe of tapestry planting combinations. It's a great challenge to create something so large and with so many plant combinations but I will be heading out to New Zealand in mid-February to start the build and I am really looking forward to the experience."
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