When the RHS Chelsea Flower Show 2024 opens its gates to the public on 21 May, the eyes of the gardening world will be drawn to the grounds of the Royal Hospital, just as they have been for more than a century. But, largely hidden from sight, things will be very different this year, because Chelsea 2024 is promised to be the greenest show ever.
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“This is an important year for the RHS,” says Helena Pettit, RHS director of shows, commercial and innovation, who has been involved in implementing widespread changes behind the scenes. “We had set ourselves a target for becoming net positive for nature and for people by 2030, and sustainability in our shows is a key part of this.” It certainly didn’t used to be. Not so long ago, as the last visitor left the showground, the sledgehammers came out, and all those gorgeous gardens were reduced to rubble, and consigned to a procession of skips.
“In the old days, there really was a lot of waste, and I am probably personally responsible for putting more plastic down on that showground than anyone else, ever. But, especially in the past two years, I’ve seen a massive shift in attitudes.”
RHS landscaping ambassador Mark Gregory
In fact, as recently as 2021, when the new Balcony Gardens category was introduced, each designer was presented with a freshly constructed plinth of breeze blocks and render to work from, which was discarded at the end of the show. But 2021 also saw the launch of the RHS Sustainability Strategy, and since then there has been a marked shift in attitude. In the run-up to Chelsea 2023, all Show and Sanctuary garden designers were asked, voluntarily, to audit the carbon footprint of implementing their plans.
Sarah Price was already preparing her exquisite Nurture Landscapes garden when she received the request, but happily embraced the challenge. “It was something I really wanted to do, but I soon discovered that there was no reliable data on which to base a calculation. If I were building a road or a house, it would have been easy, but there was nothing about planting a tree from Germany or laying concrete foundations in a garden.”
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Her solution was to work with recycled or recyclable materials, sourced along the corridor between her contractor, Crocus, and the showground, to minimise the carbon costs of transportation. “We also used some traditional techniques, such as building walls from straw bales with lime mortar render, but the footings were an innovative system of giant concrete blocks that Crocus has been reusing at the show for a number of years,” she says. “Chelsea has always been a showcase, but maybe it is time to change our idea about what is important to showcase.”
RHS landscaping ambassador Mark Gregory agrees. He built his first garden at Chelsea in 1988 and has worked there every year since, producing almost 200 gardens. “In the old days, there really was a lot of waste, and I am probably personally responsible for putting more plastic down on that showground than anyone else, ever. But, especially in the past two years, I’ve seen a massive shift in attitudes.”
Last year, Mark designed and built the Savills Plot to Plate garden and, like Sarah, found it impossible to prepare the carbon calculations he was asked to provide. “It was a good idea, but we just didn’t have the necessary information.”
“But there was a lot of interest in doing things better, and Chelsea is an amazing showcase to demonstrate what is possible.'
RHS sustainability manager Malcolm Anderson
He believes it was to the RHS’s credit that it recognised the issue and shifted approach, bringing in the sustainability expertise of design and build company Nicholsons to help develop sustainability judging criteria and facilitate carbon calculations. Mark, meanwhile, decided to set himself a personal challenge. “I thought I would see if I could make the whole garden without plastic or cement, using as many recycled materials as possible. I reused timber offcuts, got roof tiles from Facebook Marketplace and even found some joists being taken out of a chapel. It probably took me an extra 30 days of design work and research, but I enjoyed it, and I was extremely proud of the result. It wasn’t carbon neutral, but it was very, very light, and we salvaged and reused every part of the garden afterwards.” The experience left him positively evangelical. “I will definitely not use cement at Chelsea again,” he says. “I have seen the light and I’m never going back.”
RHS sustainability manager Malcolm Anderson acknowledges there are still serious issues to tackle. He has a background in construction and, when he joined the Society in 2021, was surprised to find how far behind that industry the landscaping profession was. “But there was a lot of interest in doing things better, and Chelsea is an amazing showcase to demonstrate what is possible,” he says. “For us, there are three parts to the challenge – the build, show days, and the breakdown – and in all aspects, we are tight for space, resources and time.
The flower show is sandwiched between two other events at the Royal Hospital Ground, so everything has to be done quickly, and space is so restricted that even siting extra recycling skips is a challenge. The capacity of the local electrical grid can’t meet all our needs without generator backup, and the designers all have limits on the amount of time and money they can spend on their gardens. But we have already made improvements, and there is more to come. It just takes time to turn around an event this big.”
Since 2018, the RHS has been working with A Greener Festival to improve sustainability. In 2021 it brought in biofuel generators, run on hydrotreated vegetable oil, to reduce carbon emissions. In 2022 all RHS site utility vehicles were switched to electric, and single-use plastics were banned from RHS operations in 2023 (with a back-of-house ban coming in 2025).
Not all gardens can be relocated in their entirety but this year, for the first time, not only will all eight Show gardens and seven Sanctuary gardens have gone through a preliminary Green Garden Audit to improve their carbon footprint, they will all have a relocation plan in place.
There is also a new Environmental Innovation Award up for grabs, which will be presented to one exemplary garden. There are plans to soon ban all cement-based concrete from the showground, and from 2026 onwards, all plants on site will need to be peat free. Add to this the introduction of vacuum lavatories, which use up to 90 per cent less water than traditional systems, a network of water-refill stations and a significant increase in the availability of plant-based food (which is widely regarded as a lower-carbon way to feed the world), and it is clear that the RHS is taking its self-imposed green challenge very seriously. Malcolm is pragmatic about the extent to which it can succeed. “A show like this can probably never be sustainable in the strictest sense, but it is an amazing opportunity to showcase what is possible out in the real world.”