The details of how the Government plans to fit public parks into its "Big Society" agenda are, to put it politely, scant. But with local authority spending cuts already biting, external help of some sort is likely to be needed regardless.
In the RHS magazine The Garden last month, broadcaster and Heritage Lottery Fund London committee member Wesley Kerr suggested that independent horticultural heritage bodies could step in.
Organisations such as the RHS and National Trust "could work together locally to save threatened parks, creating more active friends groups or community-gardening blogs, assisting hard-pressed councils with advice and ideas", he said. He went on to suggest that some famous gardens could adopt nearby parks, similar to the way in which independent schools assist struggling comprehensives.
With an annual income of more than £300m and staff of 4,500, the National Trust would be one of the best resourced to extend its work in this way. However, its cool response to the proposed sell-off of Forestry Commission land suggests it is in no hurry to extend its remit.
"We have more or less a complete portfolio," says chairman Simon Jenkins. "We are ready to step in if asked to, but our principal concern is our own estate. We are wary of moving out of that and into national political issues - we are proud of not taking money from the Government."
This is due to past experience, he explains. "England is chock-full of properties that could do with some help. We don't take on liabilities - that's an absolute. That almost bankrupted us in the early days. Montacute and Barrington Court were disasters."
But he adds that the trust is already negotiating with Newport City Council on how it might take over management of Tredegar House, which sits in 35ha of garden and parkland. According to a council representative: "Discussions with the trust are ongoing. They might take over running the grounds too, but they would have to remain open to the public."
So could a commercial company turn public parks from a liability into a source of revenue? The historic Trentham Estate in Staffordshire has received £100m in investment from its owner, property development firm St Modwen, not out of the goodness of its heart but because it expects the site to pay for itself.
St Modwen regional director Mike Herbert is cautiously sympathetic to the idea. "If there is a commercial advantage to the private sector in adopting a park then it's worth considering," he says. "Simply expecting the private sector to donate money is not going to happen and will always risk the sponsor withdrawing funding later."
He points to the nearby Festival Park in Stoke - a mixed-use site that includes a major area of public open space - as an example of how to use the commercial advantage. St Modwen took over managing and maintaining the 65ha park, a former Garden Festival site, on a 150-year ground lease. "The park enhances the setting of all the businesses on site - they all pay a service charge that covers the costs, so there's no cost to the public purse," Herbert explains.
"Such an approach may mean some radical decisions. There is an argument, in the right circumstances, to allow some commercial activities within part of a public park to produce the capital and revenue to secure the future running of the rest of the park."
Trentham head gardener Michael Walker adds that parks could also draw more informally on the horticulture expertise of gardens such as his. "We are always happy to share our knowledge and experience because we have tapped those elsewhere for their knowledge and experience," he says.
"While we don't have the time to be directly involved, we feel sure that the design, maintenance and use of public open space could probably benefit from the private sector perspective. We have seen plenty of public landscaping that looked great on paper and when first built, but the practicality and cost of ongoing maintenance and the way in which it would be used - and abused - did not appear to have been thought out."
Knoll Gardens owner Neil Lucas says he would give "serious consideration" to any requests for assistance from public parks. "We can certainly find enough to keep us occupied with our own garden, but I do believe that we should help wherever possible or practical," he says.
"Indeed, that is in part why we have created the Knoll Gardens Foundation - to bring our style of gardening to a wider audience and while the foundation needs to look for funding for its own work, the educational remit could cover the offering of advice and expertise to public spaces as part of a specific project."
He adds that the Dorset garden's grass-dominated planting "can and does work in public spaces as well as private gardens", saying: "Low maintenance and high aesthetic value are two of the most important factors our style of planting can bring to public landscapes - and not just in cash-strapped times."
Paignton Zoo plants and gardens curator Kevin Frediani says he would be open "in principle" to the idea of taking over management of public green spaces. "I think there would be a real potential to create an urban arboretum that takes the zoo's living collection beyond its doors and enriches the wider community," he says. "But the financial details would need to be resolved."
Birmingham Botanical Gardens & Glasshouses is unusual among botanic gardens in being wholly self-funding. As to whether the educational charity might take on responsibility for local parks, chief executive James Wheeler says: "To be honest, we have never been asked.
"However, we give input when asked about council horticultural project plans. We also try to be a good neighbour to the Guinea Gardens and the university next door and are always very supportive of any initiative aimed at educating the next generation of horticulturists. But we have limited time and resources and have to focus our time and money on keeping the gardens open before anything else."
Horticultural colleges such as Kingston Maurward are another potential source of expertise and labour for public parks. "While a garden such as ours may have a different brief to a municipal park, I am sure there are a number of aspects that could be useful for the other party, perhaps in the aspect of design and maintenance, because like parks we are also working to a tight budget," says college head of horticulture Ken Crafer.
"Having large grounds of our own gives us plenty of our own student work, though in the early stages of skills acquisition by new entrants to the sector it does take a while for some students to get to a commercial standard.
"Logistically, getting a group of students to a site at a time that is mutually beneficial may also limit the options. Colleges typically work over the academic year with a large break for full time students in the summer - when there is most work to be done."
RHS science and outreach PR manager Eoin Redahan says the society's Britain in Bloom is a ready-made example of Big Society in action. "There are literally thousands of volunteers - we estimate more than 150,000 - giving around 3.5 million volunteer hours and caring for some one-million acres of green space each year," he says.
"These volunteers are working with councils or independently, but with the agreement of their council to make local areas greener and more environmentally-friendly. We see the RHS's role as supporting and encouraging this campaign."
The volunteer ethic has long been a vital component in the work of heritage gardens. The National Trust made use of 61,000 volunteers last year, up from 55,000 in 2009. "It's an interesting time for volunteering," says chief executive Fiona Reynolds.
"If you are looking to add value and self-worth, it can be incredibly rewarding. We are now offering families the opportunity to volunteer on a one-off basis."
Situated in extensive gardens, Paignton Zoo has been developing a volunteer programme over the past three years since the arrival of plants and gardens curator Kevin Frediani.
"A principle we established early on was that volunteers in the zoo will never replace a permanent position nor be used to undertake work that garden staff do not want to do and become second-tier unpaid garden staff," he says.
The Devon Zoo also has a programme with schools to raise awareness of the potential of their outdoor spaces. "We are launching a school master gardener certificated course to train teachers in basic skills so they can not only plan their own school gardens but work with volunteers to ensure it has a life beyond the first year," says Frediani.
Despite its commercial nature, Trentham Estate also makes extensive use of volunteers. "I think it is a two-way street - providing an opportunity for volunteers to play a role in a local garden they feel passionate about supporting," says head gardener Michael Walker.