Presenter Graham Ross has a long association with Cockington Green founders Doug and Brenda Sarah, with Ross taking his Floriade tours to the gardens but he hadn't been back for about 20 years.

The Sarahs' son Mark, the gardens' general manager, said the show was filming Monday and Tuesday with Canberra turning on the spring weather.

"I was a bit nervous because Graham is an esteemed horticulturalist, as well as a TV celebrity, but the crew said they loved filming here as every shot was a quality shot," Mark said.

The episode is expected to go to air on October 2 on Prime7.