Ashley, of Scotts and Scotsdales, said at the GCA conference in Brighton, which invited all past chairmen to attend, "I am delighted to propose this toast to the GCA on this wonderful occasion - 50 years as an association helping members create fantastic garden centres which the consumer enjoys seven days a week.
"What we have today is a dramatic change from when I joined the industry 40+ years ago. The presence of so many past chairmen and chairladies along with the founding fathers is great to see and our sincere thanks to all of you for your vision in those early days of the GCA."
Ashley said changes had been "incredible" with corn seed/pet shops and nursery outlets making way for "highly professional retailers with turnovers of £20m from one centre".
He said the GC was "amazing" for sharing ideas and had set high standards.
Ashley said containerisation, the expansion of cafes, clothing, gift, shoes, pets and cards had mde garden centres a 52-week a year operation. Christmas displays make centres a "must for the whole family".
He said the young GCA generation of 20 years ago had taken "garden centre designs and product ranges to a new level".
Ashely added that the GCA has a "great future and is setting the pace for other retailers".
Past chairmen at the event included Jeffrey Bernhard, Waynman Strike, Eddie Topping, Richard Evans, FAB Newenham, Warren Haskins, Kenn Lloyd, Chris Roberts, Martin Stewart, Beryl Stafford, Guy Topping, Sue Allen, Steve Myatt, David Danning, Martin Davies, Dennis Espley, William Armitage and incumbent Julian Winfield.
Honorary members announced at the event were Alistair Armitage, Mike Cooling, Dennis Espley, Richard Evans and Richard Tarbatt.