There is a new category of show garden at Hampton Court this year – ‘Gardens For A Changing World’. Each garden considers a challenge of our times and creates a design which will address the issue and offer solutions. Both The Urban Rain Garden and Streetscape’s Holding Back The Flood consider water management issues, exploring ways of conserving our precious supplies and preventing flooding.
The youngest designer at the show, Will Williams (21) has created a symbolic garden which offers a way to prevent flood damage using alder trees (Alnus glutinosa) rather than relying on concrete barriers. The garden is inspired by the town of Pickering in North Yorkshire which was turned down for a twenty million pound grant despite its high flood risk. Needing alternative options and drawing on research from around the world, the inhabitants instigated a scheme to plant thousands of alders and create leaky dams to slow down and even prevent downstream flood water. If such lower cost, environmentally friendly and aesthetically sensitive options prove successful, it would be a positive way to approach the model predictions of a 35% rise in winter rainfall and a 25% increase in daily rainfall totals in some parts of the UK by 2080 (source: The role of woodland in flood control: a landscape perspective).
Another community aspect to this design was the construction team – all from Streetscape‘s team of landscape garden apprentices. As a social enterprise company, Streetscape provides apprenticeships for 18-25 year olds, helping them to build the skills, experience and attributes they need to fulfill their dreams and move into and retain work. This must have been a complex build with 52,000 litres of water to contain and nine alders to plant, but it all looks effortless and peaceful, showing the calm beauty of this ingenious, age-old water management system.
As well as its beauty, the woodland approach to water management also scores highly on sustainability. Will has included miniature saplings around the garden to show how the alders would gradually spread to create a self-supporting ecosystem. The alders can survive up to three weeks submerged in deep water and even longer in boggy ground whilst the flooding recedes. As our climate changes over the next few decades, the research undertaken by organisations like the Forestry Commission, flood prevention schemes such as the one in Pickering and gardens like Will William’s all help to investigate practical solutions to an increasingly important issue.
The Urban Rain Garden also offers solutions to flash flooding, but this time within a domestic setting. I liked the realistic scale of the front and back gardens in this design – allowing visitors to imagine how the raised borders might work in a real setting.
Designer Rhiannon Williams completed her Masters Degree in Landscape Architecture last year and has a keen interest in the subject of sustainability and water management. She explained that she designed the raised planters to step down in order to take water away from the house. As the water drains from planter to planter, the moisture levels reduce and the planting reflects this.
The water runs off the roof via downpipes and metal chains
In the planters nearest the downpipes, Rhiannon has included marginal plants such as the corkscrew rush (Juncus effusus), rough horsetail (Equisetum hyemale), arum lily (Zantedeschia ‘Crowborough) and Apache beads (Anemopsis californica) which will cope with raised water levels in periods of flash flooding.
As the planters continue and become drier, the planting changes, moving from hostas (‘Devon Green’ and ‘Purple Heart’) to brighter perennials like sea holly (Eryngium ‘Big Blue’), Agapanthus ‘Navy Blue’, Salvia ‘Caradonna’, ‘Blue Note’, ‘Amistad’ and ‘Ostfriesland’, and Achillea ‘Anthea’.
In times of heavy rainfall, water reaches the end of the bed system and drains into a tank beneath the garden where it can be stored to use in future times of drought. In this way the garden addresses the two key issues which are likely to become even more important over the next few years – flooding and drought, offering practical solutions in a realistic garden setting.
Holding Back The Flood and The Urban Rain Garden demonstrate ways in which gardeners and communities can use innovative, yet practical water management techniques to deal with flooding and drought. In a world where we are increasingly needing to address the challenges posed by climate change, ‘Gardens For A Changing World’ offer new ideas and solutions to give us inspiration and hope for the future.
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