Designer Tony Smith is leading a 'freestyle turfing' event at Hampton Court Flower Show.
The gold-medal winning designer and artist is buildinga 10x10m turf sculpture as centrepiece for the project, which is the first in RHS history where the society does not require a brief for a design.
Five garden designers and artists will each build a 5x10m turf sculpture alongside Smith's at the show.
Smith said: "It's the first time at a show without the RHS stipulating a plan. This is freestyle. For me it's a great relief and gives me freedom because i find planning things a bit stifling."
Adam Frost, Matt Biggs, Sim Clemens, sculptor John Humphreys and a mystery 'wildcard' designer chosen by the RHS will design the turf sculptures.
Smith has built several turf sculptures at RHS shows, including with a buried car, landscape with volcanoes and has a "vague idea" of a spiky sculpture with a turf nest in the middle for people to roll around in.
He says he will let guests have a roll on the last day of the 8-13 July show.