The Great Rosarians honoured the Norfolk gardens for their outstanding dedication to the preservation of rare and unusual roses and the national collection of Rosa species.
Judges assessed the site earlier this year and the presentation was made at a special ceremony last weekend.
The Great Rosarians are a partnership organisation between the Huntington Botanic Gardens in California and the Manhattan Rose Society in New York.
Huntington Botanic Gardens curator Clair Martin presented the award to Peter Beales during the group’s summer British rose gardens tour.
Peter Beales marketing officer Jackie Duffy said: It is a privilege to receive this award and it makes Peter’s life long love of roses all the more worth while. The gardens are a credit to the whole team and all of their hard work.
The gardens will host a special hog roast evening honouring the armed forces on behalf of Attleborough Rotary Club this Friday (25 June) from 7:30 pm.
Tickets are £7.50 and all proceeds go to the East Anglian Regiment Benevolent Fund.
For more information call Rod McClean on 01953 457728