The 20-gold medal-winning Devon-based nursery director Sara Rittershausen said: "Times have changed considerably since our first Chelsea in 1958 and it is harder to spare the enormous amount of time to prepare, as well as being increasingly difficult to make enough money out of being there. It is sad, but perhaps more of a relief to those involved."
An RHS representative said: "Nurseries change year on year, with new ones coming in as well as ones who take a year off, retire or decide to exhibit at other shows."
Burnham Nurseries will be at RHS Hampton Court Flower Show and Jardins Du Luxembourg and Taiwan Orchid Growers Association will be at Chelsea for the first time this year.
Orchids will be in short supply at the show, as Riley Growers will not be exhibiting either after a fire earlier this year destroyed much of their premises.
Subscribe to Horticulture Week for more news, more in-depth features and more technical and market info.