Loading the player..
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.