A showpiece purpose-built garden has been allowed to “go to seed” after it was ditched as the site for the BBC’s Gardener’s World programme by show bosses.

Experts estimate that the Greenacres garden complex in Edgbaston has cost licence-fee payers hundreds of thousands of pounds for its two-year stint as the base for the BBC2 programme.

The site - on a disused playing field between Winterbourne Botanical Gardens and the University of Birmingham- has been left to rot after show bosses relocated filming of the programme to the Herefordshire home of new presenter Monty Don in a bid to revive ratings.

The once-pristine garden has gone to seed with piles of earth standing in the middle of an expensively landscaped lawn and a former exotic garden, planted by former presenter Toby Buckland, now containing just one dead palm tree.

A large wooden-framed greenhouse is an empty shell and other plots previously tended by show experts, including Kings Heath-based Alys Fowler, has been completely neglected.

The BBC has refused to say how much licence-payers’ cash it spent developing the Edgbaston garden.

But gardening writer Tim Rumball accused programme makers of showing a complete lack of understanding of the views of the British gardening public. “It is horticultural vandalism,” he claimed.

A BBC spokesman said all plants and features from the show were being recycled if possible.

“The owners of the site are in discussion about how the land will be used,” he said.