Jardí Illa

Eixample is the district with the highest levels of air and noise pollution in the city, as well as the greatest deficit of green spaces. The implementation of the Superblock model in Eixample entails a comprehensive reorganization of mobility, freeing up 1 in every 3 streets from through traffic and transforming them into new green axes. This makes it possible to create a new network of 21 green corridors and 21 squares acting as environmental and social infrastructure, improving comfort and health conditions, and increasing the presence of greenery and spaces for staying in a systemic and balanced way across the entire area.

During the 2020–2023 period, a first phase was developed and implemented, including sections of four streets as well as four squares at their intersections and at the junction with Enric Granados Street. This first phase transformed a total surface area of 110,000 m², with 4.65 km of green axes and 8,000 m² of squares. Pedestrian space increased by 58,000 m², permeable surfaces rose from 1% to 15%, urban greenery expanded by 11,000 m², and 400 new trees were planted. The increase in shaded areas and the replacement of asphalt reduced summer surface temperatures by 5°C.

The intersection of Consell de Cent and Enric Granados streets has particular characteristics that distinguish it from the typical Eixample junction. First, it is located at the midpoint of a botanical route connecting Plaça Letamendi, with its imposing Washingtonia palm trees, to the historic gardens of the University of Barcelona building. These gardens are of great botanical interest, containing more than 150 plant species and some of the city’s oldest trees. Second, the site holds significant cultural and heritage value due to two architectural ensembles that are key to the image of Barcelona and Eixample: the Conciliar Seminary and the historic building of the University of Barcelona.

The proposal seeks to enhance both botanical and architectural heritage by integrating vegetation and species that strengthen the existing canopy and plant legacy. A garden is designed where there was once a crossroads, returning space to people. The new square is characterized by an explosion of greenery, extended to every possible edge of the plaza.

The planting design considered the scale of the existing tree canopy, analyzing cases where phytosanitary conditions recommended replacement. Another premise was to expand existing greenery through the planting of new trees, herbaceous plants, and shrubs. Species were selected according to current and projected climate conditions resulting from climate change, their functionality within the urban context as a shared public garden, and soil availability, always prioritizing the enhancement of local biodiversity.

To make the garden and its species legible, planting must express the passage of seasons. The growth and disappearance of vegetation thus become part of the project concept. Among the selected species, many herbaceous plants disappear during winter, creating a different garden image than in spring or summer, when many flowers bloom. In this sense, the garden embraces seasonal change, with species flowering at different times and never presenting a fixed final image, but rather a constantly evolving landscape.

At certain times of year, shrubs play a leading role; at others, herbaceous plants shape the city’s imagination. A balance between deciduous and evergreen vegetation has been established so that, although some species disappear during part of the year, the garden retains its structure.

The first of the proposed gardens is the botanical garden, responding to the broader issue of global biodiversity loss. It promotes the introduction of species that create synergies with insects and small invertebrates, improving and facilitating their relationship with urban greenery. To reinforce its role as a biodiversity refuge, an insect hotel is incorporated as a focal point for attracting fauna.

In the inner area of Jardí Illa, a low-maintenance Mediterranean-type planting scheme is proposed, recovering the richness of native vegetation suited to the city’s climate. The planting bed represents a small reserve of local flora, highly resilient and requiring little to no maintenance. The Mediterranean garden recreates a natural habitat for many native species and insects, strengthening their ecological role. Notable shrub species include Erica arborea, which attracts hymenopterans; aromatic, low-maintenance sage; and Santolina rosmarinifolia, which attracts butterflies.

Finally, the rain garden captures runoff and rainwater to return it to the aquifer. Plant species typical of wet-zone gardens are incorporated in response to the need to relieve existing drainage networks and restore subsurface conditions, while also serving as a pilot test for filtering water from the city’s paved surfaces. This garden is located along the outer edges of the square, with sufficient sunlight for semi-shade species. The different types of Sustainable Urban Drainage Systems (SUDS) used in the project include tree pits, bioretention strips, floodable planting beds, and infiltration tanks.