Crowds flocked in on the first day

It is the largest single span glasshouse in the world and houses a perfectly balanced Mediterranean landscape with a ravine, rock terrace, waterfalls and even a lake.

The gardens also feature a 220-metre herbaceous broadwalk, which take visitors from the gatehouse along deep flower borders and through a geological timewalk through Wales.

The Great Glasshouse is complemented by restored Regency-period buildings and historic parkland.

Another key attraction devised in the 10-year planning of the gardens is the interactive Simply Plants exhibition.

It allows visitors to take a journey into a world of roots and seeds and flowers, with features on gardens through the ages and legends about herbal healers.

The redevelopment of an 18th century courtyard has created a visitor centre with cafes, exhibition space, shops and cafes.

The gardens also serve a serious purpose in the promotion of sustainable development.

Battle against the elements

New and old technologies have been employed to serve the gardens energy needs, capturing and storing water and recycling garden waste.

Welsh utility company Hyder has created a water discovery centre on the site, built on stilts over a lake and is aimed at explaining water life to children.

Ivor Stokes, head of horticulture, said the gardeners had been busy battling against the elements to complete the final touches to the gardens.

"At the end of the day, the rain will save us having to water the plants in," said Mr Stokes.

"We have top mulched areas so it is not sticky and not churning up underfoot."