RHS trials development manager Mark Heath has said the society is trying to end snobbery about bedding by trialling more seasonal flowering plants.
On a trip to RHS Wisley trial grounds at the Fleuroselect Home Garden conference last month, Thompson & Morgan horticulture head Andrew Tokely questioned Heath over the RHS's stance.
Tokely said: "The RHS isn't doing enough to trial bedding. It used to, but not anymore. If 60 per cent of people grow bedding and they're not trialling it, they should be."
Heath responded: "Seasonal bedding doesn't lend itself to the Award of Garden Merit (AGM) because it is so fast moving. It's often sold not by name but by genera. We're working with the HTA, growers and breeders to find the model in which the bedding plant can have the award.
"Seasonal bedding plants have a large slice of the market. The RHS used to not touch it because it's bedding but things have changed and to not trial them is wrong."
The RHS has a large bedding container display at Wisley this year, with backing from many growers and seed companies, and with a people's choice award rather than an AGM on offer.
Future trials include New Guinea impatiens, erysimums and geraniums.
RHS Wisley curator Colin Crosbie said: "Bedding is the biggest selling group of plants in the garden but for some time people have had a very poor view of it - but where would gardeners be without them?"
On the up - Begonias
Begonias are being promoted by Thompson & Morgan as 2014's plant of the year because of work done developing new colours and on scent.
It has replaced impatiens after mildew problems forced many companies to withdraw the busy Lizzie in 2012. Horticulture head Andrew Tokely said: "There have been no mildew problems on it this year as it's been a lot drier but we're still not going to sell it, apart from New Guinea."