Environmental innovations in our Chelsea garden

Carbon & Waste

The St James’s Piccadilly Garden has been thoughtfully designed in order to minimise carbon inputs in transport, construction and use. For a design that includes several tall, complex structures this has required some innovative thinking by the engineers and contractor.

This has included:

• Use of locally-sourced, natural and recycled materials wherever possible
• Minimal use of steel and concrete in structures and footings
• Use of low-carbon materials such as geopolymer concrete
• Use of innovative carbon-negative materials.

All the key materials used in the garden are natural including:

• A timber design for the counselling cabin building which will sequester carbon and remove the requirement for concrete footings (utilising ‘screw piles’ instead)
• Unfired clay ‘strocks’ as a structural block for all the walls (in lieu of concrete blockwork). These blocks, crafted from clay-rich earth and chopped straw, not only offer structural integrity but also boast low embodied energy, promoting swift construction processes and minimal energy consumption
• Geopolymer Earth-Friendly Concrete (EFC) for wall footings, which uses no Portland Cement and emits approx 80% less CO2 than conventional concrete
• CircaBuild from Carbon 8 for paving subbases, a carbon-negative alternative to virgin aggregate. (CircaBuild is manufactured using Accelerated Carbonation Technology which carbonates and treats recycled residues from industrial plants with captured carbon. The CO2 is permanently and safely stored within CircaBuild and gives the former dust a new life, making it a circular product.)
• Recycled York stone paving slabs and natural crushed stone for paths
• Recycled natural clay facing bricks for the walls with natural lime mortars and renders for brickwork to eliminate the use of cement
• Re-use of existing water feature pumps and pipework from a previous garden, promoting re-use and reducing waste
• Natural Portland stone wall cappings and plinths, which will be re-used at St James’s with an expected life-span of several hundred years
• Timber furniture using English oak from sustainable sources.

Sustainable construction practices take precedence, with machinery and powered vehicles carefully selected for energy efficiency, including battery-operated tools. All plants have been sourced from UK nurseries and materials sourced from within the UK, and where possible within a 20-mile radius of the showground.

In tandem with its carbon-efficient ethos, the St James’s Piccadilly Garden also champions innovative waste management strategies. In addition to the use of recycled products in the construction of the garden, all of the materials will be locally re-purposed after the show in order to reduce waste to almost zero. This includes all of the plants which will be transported to St Pancras Church on Euston Road to create a new garden, and all of the hard landscape components including the timber counselling cabin, benches, all sub-bases, footpath gravels, walling and paving, which will be reused in a landscape project at St James’s Piccadilly, only two miles from the showground.

Biodiversity & Climate Resilience

The planting has been designed to enhance biodiversity and support local wildlife, both at the RHS Chelsea Flower Show and in the garden’s future home. By incorporating a deliberately wide variety of species and a layered planting structure of trees, shrubs and perennials, the garden provides diverse habitats and food sources for a wide array of species, including bees, butterflies, moths and birds.

The design also showcases approaches to planting for the future. The garden champions a range of climate-resilient trees that showcase adaptability and thrive in diverse environments. These include Ginkgo biloba, Crataegus x persimilis ‘Prunifolia’ and Koelreuteria paniculata. Several species will feature in the garden to acknowledge the resilience and regenerative capacity of pioneer, self- seeding plants and inspire us to treat our gardens as more adaptable and fluid spaces. (The garden’s inspiration extends to the resilient ‘pioneer plants’ that found a foothold in the ruins of St James’s after wartime bombings. These seeds, carried by the wind, represented new hope and growth. Seven such species will feature in the garden, serving as a reminder of nature’s resilience and its capacity for regeneration.)

Additionally, the garden includes features for wildlife such as bat boxes (integrated into the counselling cabin roof structure), a ‘St James’s’ bird nesting box and log piles offering shelter and nesting opportunities for various species. A compost heap is also integrated into the garden, supporting bug habitats and nutrient cycling.

Water, Air & Drainage

The garden showcases how green spaces can mitigate environmental impacts, conserve water resources, and enhance the overall resilience of urban landscapes through sustainable water management. Its hard landscape design utilises permeable materials such as self- binding footpath gravel and porous paving, in order to showcase how to reduce stormwater runoff and enhance natural drainage systems. Paving slabs will be laid on a permeable subbase and jointed with open textured aggregate in order to achieve a porous surface. The planting has been designed with low maintenance and low water-demand suitable for a public space.

More broadly, the garden also advocates for the integration of trees and green spaces into urban landscapes for wellbeing but also for climate resilience and improved air quality. A wide variety of densely-planted trees have been included in the design to reflect the critical role that trees play in urban spaces by absorbing carbon and pollutants from the air, cooling the city, providing habitat for wildlife and shade for users.

Societal Impact

The St James’s Piccadilly Garden is more than a horticultural display; it stands as a catalyst for profound social change. By creating a tranquil and inclusive space for reflection and connection, the garden enriches the lives of individuals and communities in a variety of ways. By housing social outreach programs such as the drop-in counselling service, the garden embodies values of compassion, inclusivity, and empowerment, fostering a sense of belonging and community cohesion. By showcasing innovative sustainability and promoting environmental stewardship, the garden inspires visitors to reconsider their relationship with nature and take action to protect our planet.

Beyond the show, the garden’s relocation to St James’s Piccadilly will profoundly impact the local community, providing a welcoming and inclusive space for reflection, connection, and engagement. From educational initiatives to community events, the garden will serve as a social and environmental hub, empowering individuals to make a positive difference in their lives and communities. Through its transformative impact, the garden demonstrates the power of horticulture to inspire change and create a more sustainable and equitable world.

Through our commitment to environmental innovation, we aim to inspire others to create a more sustainable and resilient future.