Garden designer and broadcaster Chris Beardshaw was presented with the president's medal for 2010 in recognition of the work he has done to support young people and promote horticulture as a career.
Beardshaw told how his careers teacher tried to prevent him studying horticulture, saying: "Here's Chris, he just wants to be a gardener."
He then called on horticulturists to stop being so modest. "If there is one profession that can grow out of the current situation, it is ours."
Garden writer and broadcaster Roy Lancaster received the president's award for 2011. He said the luckiest thing that could happen to a young person was to find someone else with the plant knowledge and skills to pass on to them.
"But we must do it with a smile," added Lancaster, who gave this year's James Bruce memorial lecture at the event. "There is so much fun in gardening - it is what makes life worth living."