He worked at Green-tech from 1997 until 2006 before leaving to join Platipus Anchors and more recently Hillier Nurseries.
Green-tech chairman Richard Kay said: "We are delighted that Ian is joining us as our sales Director. We are looking forward to the difference Ian will make to the business. He knows our industry really well; the challenges, the opportunities and of course the products. Some of the team already know Ian, as do many of our customers. It's an exciting time at Green-tech."
Rotherham said: "I am thrilled to re-join Green-tech. The company has really developed and expanded in the 8 years I have been away. Behind the scenes the commercial operation is a well-oiled machine, managing an extensive product portfolio of over 6000 product lines. I am looking forward to working with the team and our customers in the implementation of new product offerings and growth strategies for the business".
Other recent appointments include Lizzy Rose as admin and marketing assistant and Maggie Joynes to the reception team.