Floating gardens

Islands of aquatic, edible and bee-friendly plants are being installed in canals across the country, providing an oasis of nature and colour in urban areas

Floating Gardens

Peter Watts

Posted on 02/08/2019

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While the country’s canals are often green and blue corridors that allow nature to take root and bloom, there are some areas of the network where it’s more difficult for plant and animal life to make an impact. When that’s the case, the Canal & River Trust lends a hand by creating floating gardens – small islands of greenery that provide refuge and forage for fish, birds, mammals and reptiles, as well as a water filter to combat urban pollution. Two volunteer groups, the Lower Regent’s Coalition and The Wildlife Gardeners of Haggerston, have recently created a chain of these islands in the canal between Mile End and Haggerston with the support of the Canal & River Trust.

Tim Mulligan, a Canal & River Trust ecologist, explains the practicalities and benefits of the floating gardens. “They are a way of putting marginal vegetation into a section of canal that doesn’t have natural banks or shallow enough margins for plants to grow,” he says. “They are comprised of coir, which is made from coconut fibre and bound together very tightly in tubes, wrapped in a mesh that sits in an aluminium frame. They can be attached to one another and tied to sheet pilings or concrete walls on the off-side of the canal. They are used where there is nowhere for wildlife to take hold – there are no grooves or cracks to exploit, it’s just flat walls.”

The islands are planted with native aquatic plants such as marsh marigold, meadowsweet, purple loosestrife, ragged-robin, yellow flag iris and various sedges. The floral tops are good for pollinators such as bees and dragonflies and can provide nesting areas for birds as well as general shelter and food for small mammals, reptiles, invertebrates and amphibians. Under the water, the roots grow down to create natural shade that can be used by fish as spawning areas and refuge from predation. The plants also act as a filter for the water, improving phosphate and nitrate levels. The islands generally take care of themselves, requiring little maintenance beyond some occasional pruning.

And on top of all that, the floating gardens also look great. This is more than just a pleasant offshoot from the main ecological benefits. “The aesthetic value is really important,” says Tim. “We are very confined in the canal corridor. We can do some wildflower planting and tree planting but we’re restricted because of the number of people in London who need to use the canal. So the largest space we have to do these enhancements is actually in the channel. There have been a lot of studies about wellbeing and green space, and we can see the benefits not just from my perspective as an ecologist. It helps wildlife but it’s also good for the nine million people who are in the city. If we can provide them with green space to help their wellbeing, that’s also a bonus.”

The coir islands tend to be placed in urban areas, where the canal walls are metal or concrete, or where the water is too deep for natural vegetation to grow. Much of the planting takes place in London, where in addition to the gardens recently placed in Mile End and Haggerston, there are islands on the Limehouse Cut, the Grand Union at Ruislip and in a side pond on the Hanwell Flight. Private developers are placing coir islands at Millwall Dock, while in some parts of the River Lea, coir is being used to shore up the river bank and provide habitats for water voles. Elsewhere on the network, community gardens perform a similar role for wildlife and humans alike, allowing the canals to continue to contribute to the ecological benefit of the country.


Freda’s Garden, Aire & Calder Navigation

The stretch of canal at Knottingley between Cow Lane Bridge and Hunter’s Bridge is known as Freda’s Garden after a woman who lived in a house next to the canal – she planted her own variety of flowers along the towpath as one of the original guerrilla gardeners. After Freda’s death, the Friends Of Freda’s Garden community group was formed. They pledged to restore the garden, which had quickly become overgrown, and replanted the area with ornamental, native and nectar-rich species to encourage bees and pollinating insects. The garden is once more a blaze of colour.


Bridgewater Hall Basin, Rochdale Canal

Outside the Bridgewater Hall concert venue in Manchester is a small extension of the Rochdale Canal, which provides a waterside setting for the hall and is pretty much all that remains of the old Manchester and Salford Junction Canal. In a bid to improve the appearance of the basin as well as the ecological impact of the canal, a selection of floating islands have been installed. In cooperation with the National Trust head gardener and aquatic scientists Biomatrix, these were planted with a variety of flowers and plants based around the theme of synesthesia – the concept that sounds can conjure visions of colour. Plant species were chosen to help evoke the sense of spectacle that would come with a musical composition.


Hollingwood Hub, Chesterfield Canal

Hollingwood Hub is located at Hollingwood Lock House on the Chesterfield Canal. The building was restored and extended in 2011 and contains office space for the Chesterfield Canal Trust as well as a coffee shop, meeting room and picnic area. Volunteers and local schoolchildren have also worked on improving the garden, which was previously something of a wasteland. It’s now a green and lovely space that can be enjoyed by all visitors to the canal, and was recently awarded a Green Flag.


Birmingham Main Line

As the Birmingham Main Line passes through the centre of Birmingham it becomes increasingly difficult for wildlife to find any green spaces in which to blossom. To counter this, a number of improvements were made as part of the Main Line Canal Wildlife Enhancement project including the installation of 100m of floating gardens creating marginal vegetation on a hard-edged section of canal. These used coir rolls were planted with a variety of native species, such as yellow iris, purple loose-strife and water mint. Nectar-rich plants and herbs were also planted across the network, along with fruit trees to encourage pollinators and birds to inhabit the canal.


Bridge Street Edible Community Garden, Oxford Canal

The Banbury Community Action Group has reclaimed a section of the Oxford Canal to turn it into the Bridge Street Edible Community Garden, a space that will allow the local community to come together to grow and share edible plants and herbs. The plan is to create a positive urban green space as well as to provide guidance on how to grow food and the benefits of healthy eating. The Canal & River Trust has also recently installed 400m of coir rolls along the bank in Summertown to improve biodiversity and create habits for species, such as the water vole.


Grazing Garden, Kennet & Avon Canal

This community garden at Bradford-upon-Avon on the Kennet & Avon Canal has seen a tatty patch of land transformed into a vibrant space with fruit trees and wildflowers to attract bees and other pollinators. The intention is that locals and visitors can pick an apple, pear, plum or a few cherries when they’re down on the waterside. This is one of a number of community garden projects being run in a partnership between the Canal & River Trust and Wiltshire Wildlife Trust – other sites include Jubilee Wood, Pewsey Wharf and Great Bedwyn.


Floating garden, Regent’s Canal

This collaboration is led by two volunteer groups – the Lower Regent’s Coalition and the Wildlife Gardeners of Haggerston – with the support of the Canal & River Trust and the Mayor’s Greener City Fund. It has seen the installation of a number of floating coir islands containing native aquatic plants on the off-side of the canal in Mile End and Haggerston to improve the appearance of the canal and also create habitats for wildlife. Both groups have adopted sections of the canal and run regular events to improve the experience for visitors, making it greener, cleaner and wilder.

Jean Marie