"Chelsea is always about very smart gardens and sometimes there's an association with eco-friendly gardens as not being very smart. Maybe that's part of the reason that the idea of design and ecology are difficult to bring together."
An exception was Matthew Wilson's garden for Royal Bank of Canada, with its emphasis on water conservation. "These things come in waves and perhaps it wasn't what sponsors were looking for," said Dunnett.
"Chelsea is a snapshot of where things are. It has influence, like the catwalk does with fashion."
He called on the RHS to respond to the lack of sustainable gardens in the same way it has responded to the lack of women designers by championing their cause for future shows.