English Gardens Endangered By Warming?

John Pickrell
for National Geographic News
February 10, 2003
As global warming intensifies, the English country garden as we know it
today may soon be a thing of the past, concludes a report issued under
the auspices of the United Kingdom Climate Impacts Programme (UKCIP).

The drier summers and milder winters expected to beset the typically cool, rain-drenched British Isles as a result of climate change are likely to negatively impact the lush green lawns, rambling roses, abundant flowering shrubs, and climbing vines that are the defining features of English garden landscapes.

The report was compiled by a coalition of organizations including Britain's Royal Horticultural Society, the Forestry Commission, The Royal Botanic Gardens at Kew, and the UKCIP, a government body established to assess the impact of global warming on Britain.

Although numerous studies have examined the potentially detrimental affects of global warming on agriculture and ecosystems, Gardening in the Global Greenhouse is one of the first to examine the effects of climate change on gardens.

"Some climate change is now inevitable and although we can still influence the extent of this for the latter part of the century, the die is already cast for the next 50 years," said Chris West, a UKCIP scientist. "We want people to find out more about how these changes will affect their lives and to consider this in their plans for the future."

National Obsession

Gardening is the leading hobby in the U.K., and an estimated 27 million people—41 percent of the population—participate in some way. Garden tourism, in a country with many national heritage gardens that are 500 years old or more, is also a big business, estimated to be worth around $480 million annually.

Though estimates of the rate and extent of warming vary, some climate models suggest that temperatures in Great Britain could increase by between 2 to 4.5 degrees Celsius (3.6 to 8 degrees Fahrenheit) by the year 2080, at a rate of 0.3 - 0.5 degrees Celsius (0.5 to 0.9 Fahrenheit) each decade.

The increased temperatures are likely to lead to higher temperatures year-round, and longer, hotter, and drier summers according to the report. Spring flowers and bulbs will bloom earlier and winters will be characterized by a marked reduction in frost and snow and an increase in torrential rainfall and flooding. Snowfall, which is already rare in southern England, may decline by 90 percent in lowland and coastal regions.

In fact, average annual temperatures are rising at such an unprecedented rate that U.K. gardens are already effectively migrating south by 4 to 7 kilometers (2.5 to 4.5 miles) a year, notes the study.

Summer droughts could threaten the herbaceous borders of traditional English cottage gardens. Species including lupin, aster, and delphinium, which require highly moisture-retentive soil, will require more intensive care. Shallow-root trees and hedges such as beech may not be able to adapt to frequent summer dry spells.

Species propagated from bulbs, such as hyacinths, daffodils, snowdrops, bluebells and irises, often require cold winter temperatures to stimulate root development. British gardeners in the warmest areas may have to remove some bulbs and refrigerate them to ensure normal development, said the study.

Other important economic plants such as cherries and blackberries require a winter chill to stimulate growth of flower buds—a situation of concern for the U.K.'s fruit industry as well as home horticulturists.

Consistent Drizzle

The U.K climate is well-known for its moderate temperatures and the "remarkably even" nature of rainfall throughout the year, said Richard Bisgrove, a horticulturist and garden historian at the University of Reading and one of the report's authors.

"The picture of the U.K. as a damp, cloudy, and cool—but not cold—place has been a fair one," he said. However, as summers heat up and winters get wetter, maintaining the flawless lawns Britain is famous for will become increasingly difficult, he said.

Still, the changes might offer British gardeners some interesting new possibilities.

"Gardeners are adept at coping with the weather, and the likely climate change over the next 80 years will present exciting opportunities as well as challenges," said Simon Thornton-Wood, head of science at the Royal Horticultural Society in London. Gardeners may be able to add exotic fruits and sub-tropical plants like citrus and cannas to their repertoire, he said.

Bananas, dates, olives, pomegranates, palms, yucca plants, and other plants not usually associated with the typical English garden may also become increasingly common in the English gardens of the 21st century.

"I already grow my own figs, have grown peaches, and grow grapes and kiwi-fruits in a cold glasshouse, and I look forwarding to growing these outdoors," said Bisgrove.

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