The garden, designed by Steve Ruddy and Richard Wilford from RBG, Kew, aims to highlight the rich diversity of plant life in South Africa - a country that is home to three internationally renowned biodiversity hotspots.
This coincides with the UN International Year of Biodiversity, the FIFA World Cup, the British Museum's season celebrating Africa - including Kingdom of Ife: Sculptures from West Africa - and a new South Africa-themed Kew parterre garden in front of the Palm House.
Plants from South African nurseries include the quiver tree (Aloe dichotoma), elephant's trunk (Pachypodium namaquanum) and sweet thorn (Acacia karoo).
West Sussex-based Barnsfold Nurseries' John Turner has grown Osteospernum, while Trevena Cross has provided restios. Other plants include the Kingfisher daisy (Felicia), the red hot poker (Kniphofia) and fig marigold (Carpobrotus). Landform Consultants helped Kew staff build the garden.
Ruddy said many people did not realise that plants such as Agapanthus and Gazania originally came from South Africa. He tipped the Silver tree (Leucadendron argenteum), which grows on Table Mountain, to become popular in the UK. "If there's ever a plant to grow for the future, this is it," he urged.
The garden is the third of five planned collaborations between Kew and the British Museum and follows on from the China Landscape in 2008 and Indian Landscape in 2009. Next year it is Australia's turn, followed by an Olympic garden in 2012.
Trevenna Cross owner Graham Jeffrey, who introduced restios to the UK a decade ago, said: " We've whittled down a few varieties over the last couple of bad winters. A lot are not going to survive in temperatures of -10 degsC." He added that silver trees will not survive below -6 degsC or King Proteas at -8 degsC.
Trevenna Cross mail-order manager John Eddy supplied Berkheya purpurea, Kniphofia, Buddleja saligna and restios to the British Museum garden.
He said: "We had a shock the last two hard winters but quite a lot of South African stuff is tough. The Sydney Olympics created a little flurry of interest in New South Wales waratahs.
"People think South Africa is just proteas and they forget the other plants. I hope the football will help create interest in a wider range of South Africa plants."
Turner added: "Rain daisies don't mind the British summer. We have grown more than 10,000, but it is not a commercial crop for us - the Dutch do them at ridiculous prices."
Suffolk-based South African plant specialist Priory Plants owner Sue Mann said climate change was helping to bring plants such as Aristea, Eucomis, Agapanthus and Watsonia into more common use.
Pennard Plants owner Chris Smith, who specialises in Agapanthus, said: "We see big displays from Kirstenbosch at Chelsea Flower Show, and a lot of people will be watching the World Cup in South Africa and. Even if they are not that interested in football, they will look at the flora."