The RHS is to unveil a new Award of Garden Merit (AGM) list this month following one of the most comprehensive overhauls of the system, which could lead to annual revisions.
RHS horticulture director Jim Gardiner and Garden Centre Group horticulture head Tim Clapp will make presentations at the London Plant & Design Show on 19 February at 4-6pm on the AGMs and the new RHS plant hardiness system.
An interactive feature of six garden themes will be used to celebrate the list.
Head of horticultural trials and relations Kylie Balmain said: "The AGM was re-established in 1992 and when they did that, the council agreed to have 10-year reviews of the list. This is the second review.
"The aim of the review is to make sure we identify plants that have been superseded, and update the list where needed. Trials results show entries that need to be deleted if they have lost their AGM."
The award is given to plants of excellent garden-worthiness. The AGM is a Kitemark of quality and pest resistance, and includes more than 7,000 plants. It was launched in 1922 and reviewed in 1992 to take account of new cultivars.
Delisting may happen if a plant is no longer available to the trade, has been superseded by a better plant or has become prone to disease.
Malus 'Golden Hornet', subject to scab and poor shape, is to be replaced by M. 'Comtesse de Paris'. Tender orchids have received the AGM for the first time.
Balmain added that the RHS is to ditch the 10-year reviews because new technology and information gathering mean the list could be updated on a more regular basis. Plant chiefs are looking at an annual cycle.
"We will work with the plant committee to make sure we are looking at the AGM list every year. There are some areas we will take on as priorities where there are gaps such as hellebore and agapanthus. The review has helped us set priorities with regards to trials."
"The show's interactive central feature involves six garden themes, from conifers and woodland to kitchen gardens and house plants. It will tell the history of selected AGM plants, the meaning behind their names and why they are important. RHS and plant committees experts will hold talks and demonstrations."
Kylie Balmain, head of horticultural trials and relations, RHS.