Documents: Special Interest: Gardening In England:

How Green Actually Are Our Gardens?
by Erin O’Connor
November 28, 2011

At the inaugural Royal Horticultural Society (RHS) John MacLeod Lecture, Professor Diane Pataki encouraged the audience and city planners to look more closely at the balance between the environmental costs and benefits of urban greening.

“In general terms we tend to feel that greening our towns and cities must be good but it is not as simple as that,” said Professor Diane Pataki from the University of California, Irvine. “Indeed there are benefits but we mustn’t forget the costs such as the use of water and fertilisers.”

According to Professor Pataki the effects of vegetation on local air temperatures affects the climate in desirable ways but there are also environmental and economic costs that have to be taken into account. For example, fertilised landscapes may emit greenhouse gases such as nitrous oxide. There are very large species differences in the way that horticultural plants use water, which affects the way that gardens mitigate flooding, storm water and the urban heat-island effect.

“We need ways to determine whether our landscape designs are effective in providing the services we intended,” she said. “There is a great effort at the moment to design methods to monitor and validate greenhouse-gas emissions but there are few programmes to measure the effectiveness of green spaces in meeting the needs of city dwellers. This needs urgent attention.”

Professor Pataki gave a number of examples of work she had carried out that showed a huge variation of results. In some cases the effects were less than expected and in a few cases there was even a net environmental cost, depending on how the spaces were designed and managed.

In other cases the benefits were great and helped improved the quality of life for residents. Welcoming Professor Pataki to the lecture Dr Roger Williams, Head of RHS Science, said, “It is an honour to have a world-renowned expert on urban greening give the inaugural lecture and this speech has set an extremely high standard for future speakers.

Urban greening is an important topic for the RHS and we are working with a number of groups across the UK to carry out more research into the benefits.”

Earlier this year the RHS produced a report summarising current research into urban greening. Further information can be found at .

Professor Diane Pataki, PhD

Professor Pataki is based at the University of California, Irvine where she is Associate Professor, Earth System Science in the School of Physical Sciences and Associate Professor, Ecology & Environmental Biology and Director of the Centre for Environmental Biology, both in the School of Biology. She also advises the US Government and is on the board of Scientific Counsellors of the US Environmental Protection Agency and the Carbon Cycle Scientific Steering Group for the US Climate Change Science Programme.

About the RHS

The Royal Horticultural Society is the UK’s foremost gardening charity, helping and inspiring millions of people to garden. We do this at our gardens and shows and through our scientific research, publications, libraries and our education and community programmes. We are entirely funded by our members, visitors and supporters.

RHS membership is for anyone with an interest in gardening. Support the RHS and secure a healthy future for gardening. For more information call: 0845 130 4646, or visit RHS Registered Charity No. 222879/SC038262

  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row