Plant trials and awards

If you have ever visited a garden centre or nursery, you will probably have seen the result of the RHS trials.

A cup symbol on a plant’s label shows that it has earned the RHS Award of Garden Merit (AGM) – the RHS seal of approval that the plant performs reliably in the garden.

From February 2011 there is a new RHS AGM logo (above) that will be appearing on plant labels and displays in the nation's garden centres. 

The RHS trial of Vinca, started in 2011 and will continue to 2013. Grow periwinkle such as Vinca minor 'Atropurpurea' AGM (above) in any aspect and enjoy the pretty, windmill flowers.

Plantsman Graham Rice picks out top plants that have won an Award of Garden Merit (AGM). Canna 'Bethany' is a rich orange-flowered canna that has won an award.

Search our trial database for results from the 1920s onwards.

Follow Chris Whitehouse, Principal Scientist of Botany at RHS Garden Wisley, as he hunts down more than 70 species of colourful and dazzling Kniphofia in their natural habitat in South Africa.