Juliet Sargent, the first black designer to create a show garden at the RHS Chelsea Flower Show called for the RHS to do more to promote diversity in interview with Horticulture Week.
Sargeant's Modern Slavery Garden, commemorates the passing of the Modern Slavery Act.
"I don’t come across any other black garden designers when I’m out and about. But that doesn’t mean black people aren’t interested in gardening and design. "I think they do not culturally feel part of the horticultural scene. And you need confidence, a network of contacts and a sponsor to pull off something like a Chelsea show garden," Juliet Sargent told Horticulture Week.
"The question in my mind is whether that is being represented and whether we encourage young people of all cultures and ethnicities to come into gardening and design. I suspect not," she added.
Alan Titchmarsh hit back saying "gardening is the not the preserve of anyone" and dubbed Sargeant's comments "unhelpful".
Harrods garden Chelsea designer Diarmuid Gavin said Sargeant was right: "I am absolutely thrilled that Juliet has spoken out. I have always got into trouble for saying the RHS is too white and it is wonderful that Chelsea at last has its first black show garden designer. I hope I get to meet her."
But Fisher Tomlin said: "It is sad that Gavin and Sargeant should use this cheap tactic to fuel their own show publicity, especially as I have not seen them do anything themselves to change the situation.
"The RHS have always been very supportive of my employing young Streetscape apprentices - black, Asian and white, men and women - to gain experience building RHS features over the past four years. Some have then gone onto great jobs with top landscapers and even to Kew Gardens.
"People like Jody Lidgard with WorldSkills, Mark Gregory at the APL and Adam Frost with Homebase have done similarly. Maybe these publicity hungry designers might do best to encourage a wider diversity at Chelsea by supporting them in future."