Wilson has noticed people getting steadily more detached from nature over his working life and he and colleagues agree it has followed our increasing ability to control the indoor climate, thus losing touch with the seasons. They call it the "interior design mentality".
"Clients assume we can do anything at any time, and things will grow permanently at any time of year," he said. "People end up being in such sanitised conditions internally that they end up completely divorced from what's going on outside. They want to treat it like an interior - you can heat it, clean it, light it, cool it in summer. But the garden, the landscape, has an element of natural growth and I think some people end up quite frightened of it."
Wilson will be chairing the first day's discussion at the European Landscape Conference next month, with landscape architects, garden designers and academics coming together to discuss "the declining human relationship with nature in an increasingly urbanised world".
Panellists include the University of Sheffield's Professor James Hitchmough, landscape architect Noel Farrer and Olympic Park project lead Dr Phil Askew. All have had success in reintroducing people to nature - whether awakening politicians to the value of landscape or bringing sweeping, flower-filled vistas back into the city.
Wilson still has hope that the trend away from nature can be reversed. "Once people are introduced to nature in some way, they often love it," he pointed out. "We've had clients who have completely embraced it and become fascinated with it, which is a really fabulous thing. Certainly on a smaller scale, parents in the briefing are asking for vegetables or a productive garden area where kids can play and grow things. It has started to happen on a more regular basis than five-to-six years ago."
He credited schools and educational programmes such as that of the RHS for part of the change. But there is scope for much more input from across the industry, said Wilson. "One of the things that's really nice about the conference is it's bringing contractors, landscape architects and garden designers together. Each profession often ends up talking to ourselves - we say things are difficult or good and what we can do better - but one of the big issues is trying to get that across to a wider cross section of people."
The European Landscape Conference takes place on 3-4 September, combined with an exhibition and garden tours on 2 and 5 September. The venue is the Royal Agricultural University in Cirencester and it will be open to the public, industry, professions and academia. See www.europeanlandscapeconference.com.