Part 1: Classification and naming of plants
5. Letters and symbols
Sometimes you will see series of letters, or symbols after a plant name, and they can stand for various things:
PBR = Plant Breeders’ Rights
This is similar to when music or books are sold, and the musician or author is given royalties when their work is used. When a horticulturist breeds a new variety of plant, they can apply to have it licensed. If they are granted a licence, then that plant is given the letters PBR after its name and whenever one of the plants is sold, a few pennies of the sale money is given to the breeder. It is illegal to propagate and sell a PBR plant without paying some of the sale money to the breeder.
Search for the Plant Breeders Rights legislation and rules for propagating these plants in your country.
AGM = Award of Garden Merit
The Royal Horticultural Society trial plants for their ease of growing, disease resistance, abundance of flowering, hardiness and many other traits. For the plants that prove to be the very best in the trials, they give the Award of Garden Merit. Sometimes a symbol of a trophy is used after the name instead of the letters AGM.
Clematis
florida var. florida sieboldiana AGM
Stephen Hopkins63 / CC BY-SA 2.0