Chief executive James Barnes has left Dobbies Garden Centres after 23 years, along with finance director Sharon Brown.
Both left the Tesco-owned Midlothian company on 9 July.
A Dobbies spokesperson said: "James has led Dobbies for 23 years and leaves the business in good shape thanks to his long experience on the board. We have a good platform to bring the brand to more customers, working across all channels and with the core Tesco business.
"We will announce their successors in due course."
The news comes as a new state-of-the-art joint store with Tesco, which bought Dobbies in 2007, is being built in King’s Lynn.
The £8m Dobbies garden centre will be the first of its stores to share space with Tesco and is due to open in October.
Shoppers will enter through a single entrance and a Dobbies restaurant will join the two shops. Dobbies has 32 stores across the UK.
Tesco reported a drop in sales in the first quarter of 2013. It is investing £1bn in a turnaround plan.