Members queued at the Horticultural Halls reception desk to complain they were being charged £9 to enter the latest RHS show after in previous years attending RHS London shows for free.
An RHS spokesperson said: "In previous years we had many shows back to back around this time and unfortunately, could not get the visitors to sustain them all. This is why we made the decision to merge some of the shows together.
"In the past the Orchid Show was paired with the Botanical Art Show but in 2015 we hosted the European Orchid Conference and had two halls of Orchids only. We found that the Botanical Art Show worked well as a standalone show, but in order to provide two full halls of plants, we made the decision this year to merge the Spring Plant Fair with the Orchid Show - for which RHS members have always paid an admission fee.
"We have added an extra show this year called the Urban garden show in November and the Rose Show was added last year in June. All of the other London Shows including these new additions are still free of charge to RHS members.
"The prices for 2017 shows have not been set yet."