But Mr Keating said: ''The gardens are supposed to be about horticulture. Perhaps we could paraphrase Dorothy Parker here in its relevance to Sydney. She said you can lead a whore to culture but you can't make it think. The problem is Sydney is becoming a whore to stimulus. Its got to have another light show, now every wealthy CEO can bung on a fireworks show for his wife for their birthdays, regardless of the broad public amenity.'' He decried what he said was Sydney's rapid decline in civic decorum. The Domain had become a ''sad, deserted fair ground'' littered with temporary structures, barricades and doner kebab stands for much of the year, Mr Keating said. He took particular exception to the ''half a kilometre of Portaloos'' that confronted visitors to the Picasso exhibition across the road at the Art Gallery of NSW last year. Residents and office workers visited the botanic gardens to get away from the rush of the city and quietly take in nature, Mr Keating said. ''They don't go to actually find barricades, makeshift grandstands, makeshift restaurants, cheap audio-visual constructs and the 2013 version of what was a skyline drive-in … We are deluged as a society with audio visual on television, pay television and now so much imagery on our tablets and on our phones.''

The gardens and domain were too small to host a permanent music bowl, which Mr Keating described as a ''tasteless assault''. He questioned why the trustees needed to generate more revenue. The public would be better served if the trustees acted to protect the gardens as a green heritage space, rather than further commercial development. Mr Keating's attachment to the gardens stems in part from his formative years as a politician speaking in the Domain at Speaker's Corner. He recalls the expanse of green that existed before the Cahill Expressway cut the gardens in half. But he is also critical of a new idea to put a roof over the expressway, saying the proposal was ''grotesque'' and would create a wall that would cut the visual connection between the two gardens. Mr Keating has kept an eye on plans to develop Barangaroo since his resignation as the chairman of the panel overseeing its design in 2011, and was reportedly consulted by James Packer on design finalists for a mooted high-rise casino. Mr Keating said the Barangaroo headland park would be a ''sophisticated garden'' adding necessary green space to the city. But the expense of building the Barangaroo garden highlighted the importance of ''respecting and nurturing the one we already have'', he said. Ms Parker responded by saying anyone who was passionate about the Royal Botanic Garden was encouraged to give their ideas for the masterplan development. ''Everyone, even former prime ministers, can take part in the discussion,'' Ms Parker said.

The head of the botanic gardens trust, Brett Summerell, said government funding covered the ''basics'' of maintaining the gardens, but additional funds raised from commercial events and grant applications allowed it to run extra programs. ''Its about the quantum - having different displays on more frequently. Not just basic botany, but DNA fingerprinting,'' he said. The trust was ambitious to do more, and would hold events such as the Handa floating opera next season, Mr Summerell said. Labor environment spokesman Luke Foley blamed the trust's appetite for commercial events on the state Treasury, and warned the park was being lost for people who wanted to simply read, jog or walk. ''The renting out of the prime waterfront precinct to impresarios for months on end does not conform with the core purpose of the botanic gardens,'' he said. ''The massive pressure that Treasury places on our botanical, scientific, artistic and cultural bodies to raise more and more private funds ultimately debauches these public institutions.''