Director-general Inga Grimsey revealed she intends to relinquish the reins to the body, which has been in existence for over 200 years.
She spoke of her pride at what the organisation had achieved since she took up the position in August 2006, saying it had been a “privilege” to serve the nations garden and greenhouse enthusiasts.
It is not yet clear when Ms Grimsey will depart, but the RHS revealed it is likely to be by the beginning of 2010.
President Giles Goode-Adams noted Ms Grimsey had helped the body achieve “substantial progress”, pointing out how his colleague had helped reshape the management structure.
“The society has made tremendous progress in the delivery of its charitable mission, with the phenomenal growth of our schools programme, including two new education centres due to open next year,” he stated, thanking the outgoing expert for her efforts.
Founded in 1804, the RHS was originally known as the Horticultural Society of Lond