The holistic value of horticulture to help alleviate the effects of climate change and to help people engage with the natural world needs more emphasis, says Dr Ross Cameron. The RHS John McLeod Lecture at Lindley Hall in London on 10 November will feature Cameron taking the opportunity "in the round" to review the value of urban horticulture.
The presentation links to the RHS Greening Grey Britain and University of Sheffield senior lecturer landscape management, ecology and design campaigns. Cameron has entitled it "Repairing the rift: putting humans back in touch with their own ecology".
He said: "Essentially the speech will be about horticulture's role in the ecosystem service delivery, which is to say the benefits we derive from the natural world. Large parts of modern society seem to be increasingly disengaged from the natural world, through urban living and being immersed in new technologies. This has a number of downsides, both for other species but also for ourselves.
"A lack of engagement or understanding of nature and our own basic ecological needs has been coined 'nature deficit disorder'. Indeed, some now argue there is a significant rift between our modern society and our basic ecological and physiological requirements.
"The presentation argues that urban horticulture has a key role in helping city dwellers get back in touch with nature and natural processes. As such, it has a fundamental and perhaps unique role in helping address some of the issues outlined above. It deals with the problems of urban expansion and why it is important that our cities retain effective green infrastructure to remain functional. It also highlights the fact that horticulturists are well placed to understand the important details of green landscapes and can get the best 'services' out of these places."
He said "symptoms" of this "disorder" can include reduced physical activity and related health issues based around a sedentary lifestyle; a reduction in well-being and increase in mental health problems; fewer social skills; reduced attention span/poorer academic performance; a lack of understanding/appreciation of our own basic environmental requirements (natural cycles, where fresh water/food etc comes from); apathy and an inability to deal with environmental challenges such as climate change; less understanding of or empathy for other species; and a lack of understanding of the value that natural areas and green spaces can provide.
In an urban context this includes combating urban heat islands, improving water quality, reducing the risk of flooding, providing habitat for wildlife, opportunities for recreation and leisure and also directly providing economic gains. At the recent HTA conference in Oxfordshire, Cameron spoke on climate change and plants, concluding that resilience could be as big a factor as novelty in producing new plants as the climate warms, while flood and drought increase. He said policy makers could help the industry by introducing legislation to make developers use more plants to alleviate the effects of climate change such as the urban heat island effect and also to insulate houses.
His talk, "Gardening in a disruptive climate", said climate change predictions were for the climate to be 1-4 degsC warmer by 2050, with five-to-30 per cent more rain in winter and 20-40 per cent less in summer. There would be less snow and frost but more drought and flood and a longer growing season.
He said by 2050 half the country will "rely on irrigation to keep garden plants ticking over", adding: "Volatility is the real challenge because we're used to variation." This includes unseasonable high and low temperatures, less snow and frost and rapid oscillation between wet and dry soils.
Cameron spoke of his previous research for the RHS on how to adapt your garden to climate change. He said more resilient species, more outdoor living and more water-capture tanks would be features, as well as plants insulating houses. Plants can improve insulation by 38 per cent.
Cameron asked: "How many people sell them as living insulation?" He said he plans new research on real buildings so it can be understood by architects and also to engage with policymakers. He suggested there might be legislation around water capture and tree planting and from city planners for new gardens to help urban cooling.
Cameron suggested marketing the functional side of plants rather than just their natural beauty, perhaps as part of a "DIY kit to insulate your building". Cameron's PhD student Emma Lewis asked what plants will do well in a changing climate as part of an RHS/Project Shine-funded project.
She trialled Primula Forza, Alaska, Clotted cream and wild varieties, finding bedding varieties struggle with stress and that wild plants are more resilient than cultivars so growers should "breed for future resilience as well as colour and interest", with benefits beyond aesthetics to the fore.
Petunia singles are best for drought and doubles best for waterlogging, she added.