• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases
Staking delphiniums on the Trials Field at RHS Garden WisleyRHS Trial plants are normally grown from seed and vegetative material submitted by nurseries, individuals and breeders. Visitors to RHS Garden Wisley are welcome to view them. We also hold off-site trials at gardens and nurseries across the UK.

Trial results are used to inform the granting of Award of Garden Merit (AGM) status to plants.

See the RHS Plant Trials 2015 programme which includes a range of ornamentals, carnivorous plants and edible crops.

Plant Trials Reports

You can download Plant Trials Reports and see details of current and past trials from the RHS Trials Database. We also have a limited number of printed Plant Trials Bulletins (these contain more information than the Trials Reports) which can be downloaded, or obtained from the RHS Plant Centre at Wisley or by contacting the Trials Office (donations are requested to cover the cost of these bulletins).

RHS Horticultural plant name database

Trials also provide an important spur for RHS research into cultivated plants and their names. Use this database to search a large index of garden plant names.

View the RHS Horticultural plant name database


RHS Herbarium

Trials are an important source of material for the RHS Herbarium located at Wisley, which comprises many separate collections. The primary focus of the collections is to maintain and to acquire reference material of plants in cultivation.

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