Over one million visitors each year enjoy the benefits of the Eden Project‘s ethos of ‘exploring human dependence on plants and the natural world’ within the project’s three biomes (Rainforest, Mediterranean and Outdoor) that contain around one million plants of just under 4,000 species and cultivars – plus vast expanses of car park and entrance road plantings, associated farmland, bridleways, waterways, wetlands, wildlife and woodlands – at the 50 hectare site.
It’s an enormous and very demanding horticultural remit that is met by a 56-strong team of horticulturalists (the Green Team) and, as David Rowe, Head of Media Relations explains:
“It really is a case of ‘extreme gardening’. In the Outdoor Biome, for example, we’re working on huge slopes which we plant into and maintain. We’re trying to perform proper horticulture in a very extreme environment,” he says.
“Most of the plants were grown from seed in our nursery; others come from botanic gardens, research stations and supporters mainly in the UK and Europe. Eden is not,about rare specimens,” he emphasies, “rather, it’s about telling the story of the world through plants. We’ve got collections like rice, cocoa, chocolate and coffee which are ‘commodities’ that are everyday items to visitors, who are probably unaware of the plant from which they come It’s about bridging those gaps. That said, we have partnerships that support the conservation of rarer species, for example in the Seychelles there was a Busy Lizzie that was virtually extinct and we bred it and grew it here, then re-introduced it to its natural environment.”
He continues: “A great example of telling the story of the world through plants is the amorphophallus titanium, the world’s largest flower which comes from Sumatra. It contains an enzyme that is used to aid sleeping sickness, and we have worked with the University of Sussex in the related medical research.
“While most planting has a story behind it - for instance, we have two plants (a palm oil and a Jatropha) that are at the centre of a bio-fuel debate – some is just for the fun of it, like each spring when we plant a million bulbs simply because they’re beautiful when in bloom.”.
So, what is it is like maintaining the grounds at one of the UK’s top ten paid-for visitor attractions? According to biologist Dan Ryan, a member of the Knowledge Team: “With over one million visitors a year we understandably have concerns over trampling and unlawful cuttings, and while there can be differing views between management and the grounds team - what is deemed to be appealing to the public is not always the preferred choice of the horticulturalists – most of the time we do find a happy medium.”
Describing the establishment of Eden as a giant version of Groundforce, Dan explains that the soil is ‘gritty’ at best, “but that’s what you get when you build on decomposing granite”.
He continues: “In the beginning it was just clay and dirt, but with the help of Reading University the team created 83,000 tonnes of soil from recycled waste and about 70 per cent of that was china clay waste, which is essentially grit. This was topped up with compost from food and green waste, as well as some bought-in mulch and soil additives.
“There have been some issues with tree stability as initially, for impact, everything was planted in a very short space of time after sitting in a nursery for a couple of years. This has resulted in some of the trees not withstanding the elements because the roots haven’t taken, and these are now being replaced with younger, healthier and more vigorous trees.”.
Robert Brett, who moved to Eden from Cambridge Botanical Gardens four months ago, is the Temperate Curator with responsibility for the Outdoor and Mediterranean Biomes with 24 members of staff. With a background in farming, landscaping and horticulture, as well as a thirst for plant knowledge, Robert completed the Kew Diploma before joining Kew’s Orchid Department.
Progressing to the Glasshouses at Cambridge and completing an MSc in Environment and Development Education, he then landed his dream job.
“Eden is changing and it’s a great time to take stock of what’s been achieved. Eden is about change. Just through maturity the landscape will change - looking out you can’t see many trees but they are there and in 10, 50 or 100 years’ time it will naturally look a lot different.”
He continues: “I have a great team. They get on with their own jobs and works programmes, allowing me a more strategic role. During Autumn/Winter and coming into the Spring is a good time for the teams to revitalise the displays. It’s a quieter time of the year so there are less interruptions and it is naturally the time to lift and divide plants. The Summer is mainly about upkeep and lighter maintenance, and we deal with the public and answer any questions - usually about where the toilets are but also about plants! We also host ‘Gardeners Question Time’ type events.”
The Rainforest Biome, which is in the Guinness Book of Records for being the world’s largest conservatory and houses the tallest ‘captive’ rainforest, is where the enormity of Eden is really apparent.
The design is based on the hexagonal frame of a honeycomb and it is a structure that offers maximum strength with minimum resources. The windows are made of three layers of ETFE (ethylenetetrafluoroethylenecopolymer) which form two-metre deep ‘pillows’. The material was chosen because it transmits UV light, is non-stick, self-cleaning and weighs less that one per cent of the equivalent area of glass.
Robert explains: “The biome is home to over 1,000 plant species, including one with the largest and heaviest seed in the world, the Coco–de-mer, Lodoicea maldivica. The seed successfully germinated here in 2005 – a great achievement for a plant so rare in cultivation in the UK.
“There are many big mature specimens here, and big plants engender big thinking, he says. “The various shades of green are vibrantly interrupted by colorful and unusual plants such as the world’s largest flowering plant, the Titan Arum, Amorphophallus titanum as well as the striking colour of the flowering Jade Vine, Strongylodon macrobotrys.
This secondary forest planting scheme is slowly morphing in areas to look a lot older than it really is – the careful balance of horticulture, ecology, science, art and a little visual trickery and showbiz have created a unique fusion.”
The Mediterranean Biome houses naturalistic displays ofnative species from South Africa, California and the Mediterranean Basin. The biome is more open and light, colourful and much drier than in the Rainforest Biome; and it smells better, too! Managing the Med is not easy though, as Robert points out:
“The low light levels and low air movement when compared with the natural environment present horticultural challenges, many of which have now been overcome through experience and by refining the plant collection. It is a joy both for staff and visitors to see the many flowering plants that bear fruit, especially the citrus grove and grape vines. The bold splashes of colour from the annual spring bulbs and flower mixtures are a sight to behold.”
However, over three-quarters of Eden’s planting, and 25 plant-based exhibits, including a succession of crop-based exhibits, are outside – and the Outdoor Biome manages to maintain horticultural excellence while accommodating frequent landscape changes.
These exhibits are anything but static because Eden‘s grounds staff have also to contend with a busy timetable of events and concerts including Christmas markets, parades, ice rinks, art installations and rock concerts – for which the capacity is 5,000.
To further illustrate how grounds professionals across the industry have common problems, the Eden team also needs to ensure visitors don’t trample or damage plants and that the grass surrounding the theatre is kept in good condition all year round.
Eden has developed a world-class plant health operating procedure, and through PlantNetwork collaborated with the Central Science Laboratories, the Royal Botanic Gardens Edinburgh and the Royal Botanic Gardens Kew to produce Guidelines on Legislation, Import Practices and Plant Quarantine for Botanic Gardens and Kindred Institutions.
Eden’s rigorous programme, using isolation houses, catches pest and disease problems at an early stage, while the integrated pest management system in the biomes uses cultural methods (removal of infested plant parts), ‘soft’ chemicals (soaps and oils) and 33 different types of biological control (bugs that eat bugs), some of which are even lifted up to the Rainforest Biome canopy using bamboo pots on pulley systems. UV lightboxes catch pests and monitor numbers.
The Eden Project - facts and figures
The site near St Austell, Cornwall, started out 10 years ago as a redundant china clay pit the size of 30 football pitches. The pit was carved to create a flat bottomed bowl which involved moving 1.8 million tonnes of dirt. A lot of work was done on the steep side slopes to create safe angles and terraces. Once the sides were stabilised with over 2,000 rock anchors they were sprayed with plant seed, soil and fertilisers.
Each area of the site has its own soil requirements. The rapid growing plants in the Rainforest Biome require a rich organic soil capable of holding large amounts of wwater and nutrients. The slower growers in the Mediterranean Biome used a sandy mix which holds less of both. Composted domestic green waste is used in the Outdoor Biome. Three drainage systems are in use (instigated after two months of rain at beginning of the construction when 43 million gallons of rainwater had drained into the pit). Clean water is piped in for drinking (minimal consumption); Run off or ‘grey’ water is used for sanitation; Rain water (collected from the biomes) is used for irrigation and to create the Rainforest Biome mist.
“We try to cultivate and grow without chemicals but sometimes it is an unavoidable necessity,” says the Knowledge Team’s Dan Ryan. “The biggest problem we face is pests and diseases in the biomes and DEFRA occasionally encourages us to do remedial work. Whenever we have a notifiable pest we advise DEFRA and act on its advice.
“Our ‘integrated pest management system’ employs birds, lizards, tree frogs and preying mantis which live in the biomes but are not part of the exhibit - so they are, quite literally, ‘employed’. In the early days, we held a zoo licence but the inspectors felt that because the animals weren’t on display and for public enjoyment they were better described as ‘employees’.”
Underpinning much of what is done at Eden is the nursery team at the Watering Lane satellite site – the home of everything from nurturing new crop plants to keeping certain plant treasures in trust for new projects, as well as researching new technologies to make horticultural plant production more sustainable. Eden works hand in hand with the social firm People and Gardens, who use horticulture as a training and life skills development opportunity for people with learning difficulties.