Marco Hoffman, the Dutch taxonomist, and Fergus Garrett, head gardener at Great Dixter, in East Sussex, will speak at the event, held at RHS Wisley on 4-7 July.
They will cover subjects including the conflicts and challenges of trials and explore tensions between the market and horticultural responsibility.
"We will explore the challenge of trialling, the rights of plant breeders and how to recognise plant hardiness," said RHS director of horticulture Jim Gardiner.
Other speakers include US horticulture professor Allan Armitage and the president of Terra Nova Nurseries, USA, Dan Heims.
For further details, see www.rhs.org.uk/ornamentals2011.