Where military equipment was once stored, the Federal Garden Show opens in Mannheim on April 14: the main focus of the garden show is on the site of the former Spinelli barracks, but a cable car will also take visitors to the inner-city Luisenpark. Read here how the planners from RMP Landschaftsarchitekten are integrating relics of the barracks and what else makes BUGA Mannheim stand out.
Where military equipment was once stored, the Federal Garden Show opens in Mannheim on April 14: the main focus of the garden show is on the site of the former Spinelli barracks, but a cable car will also take visitors to the inner-city Luisenpark. Read here how the planners from RMP Landschaftsarchitekten are integrating relics of the barracks and what else makes BUGA Mannheim stand out.
Mannheim has big plans for 2030. In its mission statement, which the city has developed together with its citizens, it commits to sustainable, climate-friendly urban development. The Federal Garden Show 2023 is intended to give a boost to the visions in the mission statement. Mannheim has already made clever use of the garden show as an instrument for its urban development twice: in 1907 and 1975. The Kunsthalle Mannheim and the water tower still bear witness to the 1907 International Art and Horticultural Exhibition, while the Luisenpark and Herzogenriedpark bear witness to the 1975 Federal Garden Show. But even more was happening in the city at the time, including the Neckar Promenade, the pedestrian zone and the Herzogenried district, which were created in the wake of the show. Mannheim is now hoping that the 2023 Federal Horticultural Show will provide similar long-term impetus for the implementation of the ambitious goals of the 2030 vision. Last but not least, the city wants to become climate-neutral within a few years.
The guidelines for the topic of climate were already laid out in the competition for the 2014 Federal Garden Show, at a time when thinking about climate was still considered almost avant-garde: Mannheim had intensively considered which important open space corridors should be kept free in the future. The opportunity arose for the north-east green corridor after the withdrawal of the American armed forces. They gave up their barracks, which gave me the chance to keep the corridor from the inner-city Luisenpark across the Neckar to the Vogelstangsee lakes free as a fish air corridor. This is essential for Mannheim, as 225 days of inversion weather are predicted for the city on the Rhine in 2050.
Tropical nights in summer will become more frequent. Two degrees Celsius less in the districts along the green corridor will bring considerable relief. The former Spinelli barracks, on whose grounds the main focus of the garden show is located, is an important part of this corridor. There were also clear specifications for this in the competition: to ensure the supply of fresh air, a 150-meter corridor was to remain free of trees.
Whether the Federal Horticultural Show is the right strategic tool for implementing the climate targets was, however, still a matter of controversy even after the competition, recalls Stephan Lenzen, who was awarded the contract for the horticultural show with his office RMP Landschaftsarchitekten in 2016: “The first year was mainly a matter of persuasion.” Although the city consulted citizens in advance and also involved them in the planning phase via citizens’ forums, the majority in favor of the Federal Horticultural Show was extremely narrow, so much so that it even became an issue in the mayoral election campaign. Peter Kurz, the current Lord Mayor, sees the Federal Horticultural Show as “an opportunity, as in 1975, to further change the view of Mannheim in a positive way and to accelerate this change towards a sustainable city.” Not least because the focus is on “sustainable and modern urban development that renegotiates nature conservation, climate justice and biodiversity”, he explains in the brochure on the framework concept for the Federal Horticultural Show.
In 2017, the local council finally made the key decision for the north-east green corridor and the Federal Garden Show. The last areas of the barracks were handed over in 2020. 80 hectares of built-up barracks areas were unsealed; the climate park was created there, almost half of which belongs to the so-called Große Weite. It is to remain treeless as an open center so that fresh air can circulate. This area was developed as a habitat for flora and fauna: Numerous species feel at home on the poor soil.
A neo-dune rises up towards the adjacent Freudenheimer Au as a dry biotope and embankment to the Am Aubuckel road. Opposite this extensive area of the new park is the intensive part, the so-called Parkschale. The narrow strip borders Mannheim-Käfertal and -Freundenheim, where a number of new residential buildings are being built on the edge of the park. Axes lead from the estate into the park. There, in the park bowl with numerous opportunities for play and sport, 1,300 new trees are now growing. Because: “There were maybe five existing trees,” recalls Stephan Lenzen.
However, the Spirelli barracks were less a residential barracks and more a storage facility for large equipment such as tanks. Accordingly, the halls were densely packed. Nevertheless, the landscape architects have preserved relics wherever possible. Here a concrete path or a tank loading ramp, here a guard’s house. The largest surviving building is the U-Hall, which looks like an elongated horseshoe. The former truck repair hall is not beautiful in the classical sense, says Lenzen, but it is impressive in its dimensions and has an appealingly rough charm. Hütten und Paläste Architekten from Berlin won a competition for the subsequent use of the hall. In order not to obstruct the supply of cold air in the green corridor, the U-shaped hall was reduced from its original 21,000 to around 13,000 square meters and its outer walls were broken up. Ribbed concrete structures and steel scaffolding were left behind and planted with climbing plants, grasses and wildflowers. Some things were dismantled by hand, as glass blocks, ceiling lights and much more are to be reused.
The exhibition areas for the garden show are located in and around the U-Halle. Restaurants and a youth club have already set up shop there. There is a good chance that this location with its industrial character will become a new attraction in Mannheim, not least because Spinelli Park and the entire north-east green corridor are connected to the city center by a fast cycle path. Another plus: for the BUGA Mannheim, the hall made it possible to concentrate the exhibition areas and not to obstruct the permanent facilities with exhibition contributions. The themed gardens directly adjacent to the hall are located between temporary embankments planted with 2,300 climatic trees. These will be planted out in the city of Mannheim after the Federal Garden Show, so that the exhibition grounds serve as a tree nursery and experimental field for various tree species.
At the time, the competition not only included the Spinelli barracks, but also the neighboring Freudenheimer Aue, an old Neckar bend with fields and allotments. Stephan Lenzen would have liked to be able to relocate the dividing road Am Aubuckel, but this was not possible. As a result, a viewing bridge now spans the Freudenheimer Aue, which will become a pedestrian bridge after the garden show, bridging the road and the difference in height to the Aue. A new floodplain watercourse with a reed belt has been created there, partly sealed with found clay. The vision is for the floodplain watercourse to be connected to the Neckar in 2024. The former Neckar loop will then become part of the Neckar again.
Unlike Freudenheimer Aue, Luisenpark was not originally intended to be part of the Federal Garden Show. But Stephan Lenzen has now planned several garden shows and can say from experience: a show on the outskirts of a city has a hard time. And Mannheim had a popular park in the city center thanks to the successful Federal Garden Show in 1975. For this reason, a cable car connects the Luisenpark with the Spinelli grounds via the renaturalized Neckar – also a BUGA Mannheim project.
To ensure that Luisenpark remains attractive in the future, it was carefully modernized according to the plans of Bez + Kock Architekten. In the new park center, the main focus was on building construction, an underwater world and the South America House. Farm buildings were also relocated so that the park gained additional space.
The garden show thus spans the arc from the landscape architecture of the 1970s, when the aim was to create recreational spaces in the inner cities, to the climate park of today. In what Stephan Lenzen describes as a greatly reduced design for the former Spirelli barracks, the focus is also on climate adaptation and nature conservation.
The entire BUGA Mannheim has set itself the goal of being an experimental field for climate adaptation strategies. University projects are being implemented on the Spinelli site. For example, researchers at the Karlsruhe Institute of Technology KIT have developed an irrigation system that prevents rainfall from seeping away directly and instead holds the water in a storage basin with appropriate soil substrates close to the surface. This system will protect the new trees in the park bowl from drought, for example.
More than ever, the challenge is to give people and nature equal space in the city and to always keep climate protection in mind. This Federal Horticultural Show shows this very clearly.
Read more: BUGA Mannheim is not the only horticultural show taking place this year. Find out when and where here: All garden shows 2023.
