An AGM indicates that a plant has been recommended by the Royal Horticultural Society (RHS). The AGM is only awarded after careful assessment and draws upon the wealth of experience and knowledge held by the RHS Plant Committees and staff. Assessments can take place in a number of ways, such as trials at one of the RHS’s gardens, visits to specialist collections and round-table discussions drawing on the expertise of Committee members. The award is for the species or cultivar, not an individual plant.

The AGM also indicates the hardiness rating and is a practical guide to the suitable growing conditions. The distinctions for hardiness are as follows

H1		Plants require the protection of heated glass
H2		Plants requiring unheated glass
H3		Plants hardy outside in some regions or particular situations, or, which whilst usually grown outside in the summer need frost free protection in the winter.
H4		Plants hardy throughout the British Isles

www.rhs.org.uk