Huge swathes of England could take on a Mediterranean look within 50 years as native woodlands are threatened by warmer, drier summers, say scientists.
Fields of sunflowers could replace the traditional English landscape
Olive groves, vines and sunflower fields could become hallmarks of the landscape in South-East England as global warming changes conditions.
Experts also say the English country garden is unlikely to survive in the South East in its present form.
Rolling lawns and herbaceous borders may be ousted by palms and eucalyptus.
By 2050 summer temperatures in the South-East of England are expected to be 1.5 to 3C warmer than they are now.
This could rise to 6C by 2080 if current global warming trends continue. Meanwhile rainfall will be cut by a third.
Scientists, at a two-day climate change conference at the University of Surrey in Guildford, conjured a picture more reminiscent of the South of France than the South Downs as they looked at the implications of global warming for Britain's native trees.
The Mediterranean climate of southern France will not be exactly replicated in England, since levels of sunlight here are lower, they said.
But experts predict many trees native to southern France will become much more common further north.
These include walnut, poplar, sweet chestnut, plums, kiwi fruits and vines.
Corsican pine was predicted to become the forester's tree of choice.
The traditional sight of bluebells and snowdrops a shady wooden glades could become a thing of the past if new tree varieties and early perennials deprive them of light and nutrients.
Fields of sunflowers and sweet corn could become commonplace, while olive and eucalyptus trees will form trusty additions to gardens and parks, along with silk trees, Persian lilac and pistachio.
Native woods of oak, beech, ash and Scots pine from Scotland to Cornwall are thought to be most at risk from climate change - with beech trees of the drier, warmer south of England set to be affected first.
Although most other varieties are expected to survive, careful long term planning will be needed, it added.
Britain's fauna will also be affected as the annual cycle of mammal, bird and insect species may no longer be synchronised with the species on which they depend.
Populations of deer and rabbits are likely to increase and parakeets, which are already common in London, are set to multiply.
Gardeners in the South-West of England are advised to change their planting habits - swapping beech trees and hedges for Trees of Heaven, Holm Oak and Eucalyptus.
Guy Barter, from the RHS, said: "Lawns and herbaceous borders are going to be difficult to maintain, especially in areas of water shortages.
"For the average gardener there may be more opportunities but it's going to be very difficult for the National Trust, for example, to maintain the character of its historic gardens."
The RHS also warmed gardeners not to fall into the trap of planting trees now that would survive in a more tropical climate in 50 years time .
Professor Jeff Burley, director of the Oxford Forestry Institute at Oxford University said scene was going to change.
"It's already happening - you can already see fields of sunflowers."
Mr Barter said it would be a shame to lose the traditional English country garden.
"But in a way I feel we've gone too far now to be able to go back."
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