The MA is popular, seen as elite and generates revenue. Yet it could be targeted by heads of the University of Bristol, according to course tutor Professor Timothy Mowl.
The faculty must save £1.5m and cuts are being focused on the department for archaeology and anthropology, which includes the garden history MA. Four out of 14 staff from the overall department could lose their jobs and if Mowl is one of them, the course, with 23 postgraduates, could be jeopardised.
"To put that sort of national-leading MA at risk is unwise," he said. "We are incredibly successful and enjoy a strong profile."
He pointed out that no-one had yet been told they would lose their jobs and the university departments were still in talks with each other and the unions.
A source asking not to be named said: "It's strange that a successful and revenue-generating department should be targeted. I think it's perceived as too out-of-the-box and lacking research focus."
A university representative said: "We are finding ways of reducing costs in order to cope with the financial pressures affecting the higher education sector as a whole.
"Bristol's MA in garden history has not been identified as at risk or earmarked for closure. But there is no such thing as a permanent guarantee. All academic programmes are subject to review, but it would be quite wrong to suggest that our MA is in the firing line."
Society of Garden Designers chair Annabel Downs said: "This shouldn't go unnoticed and uncommented on. Once something is lost it's virtually impossible to resurrect it and you lose the staff elsewhere or abroad. It is vital that departments are kept open.
"Their closure can unhinge other organisations such as English Heritage and National Trust. It doesn't just have an impact on design."