Wolfgang collected many of the garden's rare plants

As curator of the ambitious west Wales horticultural project, Wolfgang Bopp played a leading role in developing the garden's design, oversaw much of the planting, and travelled the world tracking down rare plants.

But now Mr Bopp, 35, has accepted an offer to become curator of the Sir Harold Hillier Gardens in Hampshire - just a month after the troubled garden was offered a rescue package by the Welsh Assembly Government.

Speaking to BBC Wales, German-born Mr Bopp admitted he had thrown his heart and soul into establishing the garden for more than six years, and he was reluctant to let go.

But, now that the garden had been thrown a life-line, he felt the time was right to make a move.

"I was first approached in January and asked to consider whether I would apply for the post," he explained.

"Now that the garden is looking to be coming out of the crisis, it is an opportune time for me to announce that I'm moving on."

Mr Bopp was one of the first members of staff to be recruited for the Carmarthenshire garden, and arrived when it was little more than a building site.

The great glasshouse - the impressive focal point of the site, which is the largest single-span glass structure in the world - was still in the planning stages.

"When I came here, it was just an even site," he said. "I think they were just starting to dig a hole."

Among the many things Mr Bopp will miss will be the exotic plants he collected for the glasshouse - including many he tracked down while on honeymoon with his wife, Janet, a fellow horticulturalist who worked at Middleton.

The glasshouse has particular memories for the couple, as they were the first to be married there.

Mr Bopp is looking forward to his new challenge, taking charge of the 180-acre Sir Harold Hillier Gardens, which has the most extensive collection of hardy, woody plants in Britain.

It was originally created as a private garden and arboretum more than 50 years ago, and is now owned by Hampshire County Council.

Meanwhile, work continues to develop Middleton and turn it into a successful operation.

"It's been my baby for six-and-a-half years, and it's been fantastic working with the team here - but I'm sure I will come back many times to see its progress," Mr Bopp said.