Jinny Blom, Debbie Roberts and Ian Smith of Acres Wild, Andy Sturgeon and Brita von Schoenaich have been booked for the event, to be held on 16 November at Imperial College, London.
They will explore what influenced them to become garden designers in the first place and what has influenced their design approach since then, under the theme The Source.
The conference will be chaired by James Alexander-Sinclair, who worked as Father Christmas, a gossip columnist and a Mr Whippy salesman before finding gardening and garden design.
The society is offering an early bird rate of £104 for members or £77 for student members, with members of related organisations paying £125 before 27 September.
For booking form click here or phone the SGD office on 01989 566695.