AGM versus AAS plants

W. Ray Hastings

Whenever I am reading various gardening or landscape design magazines, books, or online sources, particularly from the United Kingdom, notable plants will be listed by their scientific name followed by AGM, such as Galanthus plicatus AGM. The Royal Horticulture Society established a multi-trial testing for selected plants to examine their performance over time. If awarded the Award of Garden Merit (AGM), designers and consumers can feel confident that the species will perform well for them, providing the plant is given similar conditions to the tests. That last bit is interesting, because the Royal Horticulture Society (RHS) will perform a nationwide evaluation at various RHS gardens and will consider other submitted reports by professional and amateur gardeners alike. This is a fantastic way to encourage consumers to try new plants in their own gardens. Their efforts prompted me to wonder, does the United States have a similar testing program?

I became aware of the All-America Selections (AAS) designation when I recently planted Zinnia grandiflora 'Profusion Cherry' where the label listed AAS. The All-America Selections is a non-profit, first proposed by W. Ray Hastings, appearing to model after the AGM program, but its notoriety does not yet have the same gravitas as AGM. Regardless, AAS can be highly informative to American gardeners and designers. One of the additional benefits of following AAS and AGM is that they both have designated gardens where the public and professionals can view their testing. For example, here in California, AAS lists five gardens on their website. Now I am on a mission to visit them and see what tests are occurring. In England, one of my go-to gardens to visit is RHS Wisley for viewing their spectacular displays and testing grounds.

Garden locations listed on the All-America Selections website.