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The Royal Horticultural Society's Award of Garden Merit (AGM) aims to help gardeners make informed choices about plants. The award indicates that the plant is recommended by the RHS.


For ease of reference you will be able to see which plants have the award by the presence of the AGM logo (as above) in the individual plant descriptions.


The RHS state that the AGM is intended to be of practical value to the home gardener. It is awarded therefore only to a plant that meets the following criteria in that it must:

  • be of outstanding excellence for ordinary garden decoration or use
  • be available
  • be of good constitution
  • not require highly specialist growing conditions or care
  • not be particularly susceptible to any pest or disease
  • not be subject to an unreasonable degree of reversion in its vegetative or floral characteristics

Plants of all kinds can be considered for the AGM, including fruit and vegetables. Though growing conditions and plant types may vary, the purpose of the award is always the same: to highlight the best plants available to the home gardener.


Every AGM plant has a hardiness rating, which is intended to serve as a general guide to growing conditions, and should be interpreted as follows:

  • H1: Requires heated glass
  • H2: Requires unheated glass
  • H3: Hardy outside in some regions or particular situations or which, while usually grown outside in summer, needs frost-free protection in winter (e.g. dahlias)
  • H4: Hardy throughout the British Isles
  • H1-2: Intermediate between H1 and H2
  • H2-3: Intermediate between H2 and H3
  • H3-4: Intermediate between H3 and H4
  • H1+3: Requiring heated glass; may be grown outside in summer

The full list of AGM plants, revised in February 2013, is available as a downloadable pdf here: