Since 2011, nearly 1,000 new groups have joined the RHS Britain in Bloom and RHS It's Your Neighbourhood campaigns, and a record 80 finalists have been nominated to represent their region or nation in the 2013 Britain in Bloom UK Finals.
RHS It's Your Neighbourhood, set up in 2006 to cater for smaller volunteer groups such as residents' associations, has grown to more than 1,680 groups, an 80 per cent increase in six years and a 21 per cent uplift since last year.
RHS regional development head Andrea Van Sittart said: "Thanks to the legacy of London 2012, the power of volunteering has never been more widely recognised or appreciated. More Britons are prepared to donate their time and energy to worthwhile projects and we feel this could have played a part in the rise in volunteers joining their local gardening groups or setting up their own.
"More and more people are aware that helping improve their neighbourhoods can change lives and boost people's confidence, health and happiness. The Britain in Bloom campaign is making a difference, and people want to be a part of that."
About 800 volunteers from this year's 80 finalist communities will take RHS judges on a tour of projects and initiatives in July/August.
Results will be announced at an awards ceremony in October.