Goodbye to the English garden?

Hot summers and wet winters could kill our best-loved plants, reports Andrew Johnson

Gardeners will have to change their ways and their plants to deal with the drier summers and wetter winters that global warming is bringing, ministers believe.

The advice comes as the traditional peak season for gardening approaches. Nurseries and superstores are now at the height of their plant-selling period, and the Chelsea Flower Show opens next week.

The show this year strongly reflects the trend for Mediterranean-style plants suitable for dry conditions. But many of the "dry" plants being pushed by designers and garden centres, will, say Royal Horticultural Society experts, be unable to survive the expected climactic change without a drastic alteration in gardening methods.

According to the latest evidence, revealed at a confidential government briefing with the RHS last week, Britain will experience a steady increase in flooding in winter.

Michael Meacher, the Environment Secretary, said: "It will have an impact on soils, on the timing of the growing season, and on the varieties of plants that can be grown."

The RHS is urging its members to do extensive drainage work to protect gardens from the rising water levels.

Ironically, record numbers of "dry gardens" and water conservation features appear at the four-dayChelsea Flower Show starting on 21 May – a direct response to the warmer climate, say the organisers. And garden centres are already making millions from the vogue for Mediterranean or desert plants as summer temperatures rise.

But the green-fingered who turn to the "hot look" could be wasting their cash unless they sort out winter drainage for their gardens. "Nothing can survive in waterlogged conditions, neither Mediterranean nor native plants except for trees like willow and poplar," said Guy Barter, head of the RHS advisory service.

He added: "Olive trees, grapes, avocados and even banana plants could all become common garden features. The air could be full of the scent of acacia. Water will be expensive so lawns may disappear. We will also see more gardens with heat-resistant trees, and cacti and yucca. But the problem will be flooding in winter."

While lemon trees and eucalyptus may replace rhododendrons and lawns, thanks to global warming, all the hard work of gardeners will be undone unless they manage to cope with the severely wet winters that will occur.

The Royal Horticultural Society, meanwhile, is co-funding a Reading University report with the National Trust into the effects of climate change. The trust is concerned about its historic gardens.

"If you are trying to preserve a historic garden that is up to 400 years old and the very climate they were created in has become historic, then you have a problem," said Mike Calnan, the trust's head of gardens.

This month's edition of the Meteorological Society's magazine Weather reported evidence that the growing season has been lengthening by a day a year; in 2000 it was the longest on record, at 330 days. "If the trend continues, it is possible we'll have a year-round growing season within a generation," said Dr Tim Mitchell of the Tyndall Research Centre.

Mark Anthony Walker, designer of a recycled water garden at Chelsea, warned that traditional English rural scenes could vanish. "A [partly] dry climate isn't all it's cracked up to be. Beech trees are having a hard time because of drought. England is England – I have a very pastoral view of it, and I would hate to lose it."