A design inspired by the shape of a butterfly, has won the £25m competition to remake one of Scotland's most prominent public performance spaces.

A US based design company, wHY, and the Edinburgh designers GRAS have won the competition to revamp the Ross Pavilion and the West Princes Street Gardens in the green centre of Scotland's capital.

The design, which involves a series of grassy new hills, "sculptural seating" and an undulating promenade, will feature a visitor centre with a cafe, and a "flexible platform for the imaginative arts and cultural programming."

The search for a winning design for the project attracted submissions from 125 teams, 400 firms and bids from 22 different countries.

Norman Springford, chair of the jury, said: "As is always the case with initiatives of this size and stature, the jury had a hard job.

"We are confident however that we have a winning concept that embodies an imaginative ensemble landscape approach, creating a wonderful stage for our iconic Edinburgh Castle.

"In addition, the design concept offers a creative energy and a series of unique elements which will all combine to create a new and contemporary landscape."

The design is inspired, the designers say, by the gardens' geology and history, and a butterfly shape.

The pavilion "folds" into the landscape, so that the view of the castle remains "the main visual event."

The scheme, they say, also increases the amount of "green space relative to hard surfaces" and is "human scale with moments of drama… activating four layers of meaning within the Gardens: botanical, civic, commemorative and cultural."

Mr Springford added that the Jury had praised the winning team’s concept design as "a beautiful and intensely appealing proposal that complemented, but did not compete with, the skyline of the City and the Castle."

wHY is a company of architects, landscape designers, with offices in Los Angeles and New York.

According to the Los Angeles Times, wHY’s founder Kulapat Yantrasast, "is increasingly sought after in the cultural sphere for his ability to skilfully conjure environments that suit the needs of art".

wHY will now work with the Ross Development Trust, the City of Edinburgh Council, and consult with the public.

Construction is "expected to begin in 2018", the council said.

He added that the winning design "respects and enhances the historical context and backdrop of the Castle and the City, whilst creating new heritage and increasing the green space within the Gardens."

The competition jury met on July 11 to interview the seven teams shortlisted for this initiative, and unanimously selected wHY as the winner. Their team includes Edinburgh-based design studio GRAS, Groves-Raines Architects, Arup, Studio Yann Kersalé, O Street, Stuco, Creative Concern, Noel Kingsbury, Atelier Ten and Lawrence Barth.

Andy Neal, a trustee of the Ross Development Trust, said: ‘It is always a tough job to select a winner when you have such a strong shortlist of entries.

"We are looking forward to working with wHY to develop our vision for West Princes Street Gardens...it’s an exciting time for the city.’

Kulapat Yantrasast, the founder and creative director of wHY, said the plans represent a convergence of "ideas, experience, nature and people."

Mark Thomann, wHY’s Landscape Design Director, added: "This is a special opportunity for a special place, not just for Edinburgh but the world. The new Ross Pavilion and Gardens draw from the rich natural history, heritage and creative spirit of Scotland, embodying a model approach for integrating public architecture and urban space in a top global city."

Councillor Donald Wilson, Edinburgh’s Culture Convener, said:"We have seen some of the most influential architects and landscapers join forces to compete to design the new Ross Pavilion.

"The huge international interest in the competition is testament to Edinburgh’s standing as one of the world’s most beautiful and creative settings for live performance.

"All of the shortlisted teams put forward fantastic ideas but wHY’s Butterfly concept received the jury’s collective support.

"The chosen design makes the most of the natural surroundings of Princes St Gardens and focuses on connecting people to the city, the stage and the view of Edinburgh Castle."