The 14 judges have this week been appraising the entries as they visit 69 towns, villages and cities in a bid to uncover the country's finest horticultural skills.
RHS Britain in Bloom chairman of judges Roger Burnett said: "The national judges will be looking for excellence in floral and permanent planting (and) how issues surrounding conservation and recycling are being addressed, together with environmental quality.
"They will also want to know how Britain in Bloom is being promoted at a local level and meeting this year's theme of Local Roots."
The RHS Local Roots Award is a special discretionary award presented to the community that best encourages links between local history and cultural diversity.
Following the completion of judging on 15 August, the winners will be revealed at the RHS Britain in Bloom Awards Presentation at Chester Racecourse on 24 September.
Burnett added: "We will be looking for how local issues that affect everyday life are being addressed 365 days a year through community horticulture.
"For example, planting up a run-down area in a city centre can cut petty crime."
Winners must show outstanding efforts in all of the four pillars of the Britain in Bloom campaign: horticultural enthusiasm; environmental friendliness; community involvement; and sustainability.