City Garden Groningen rooftop park

The state office of the executive organisation of the Ministry of Education (DUO) and the Tax Administration in Groningen rises from the landscape like a giant, white sailing ship. The building, standing ninety metres tall, dominates the entire surroundings. With the exception of a couple of old giants, all trees are dwarfed. LODEWIJK BALJON landscape architects brought back the human scale by designing an ecological garden around the building, in which safety is central. Multi-stem trees with a natural look give this city garden an atmosphere and experience.

Know-how to grow

The location is around thirty kilometres from the Wadden Sea coast and coastal winds are still noticeable here. Around the tall building, there are fall winds and measures need to be taken to break these. The building itself has fins, that guide and weaken the wind. At ground level, a pattern of green wind screens has been designed. “It was a challenge to break the force of the wind and still to keep the garden visually open. The spatial experience and social safety of the visitors could not be threatened. The solution was found in three-metre tall screens, slightly bent and covered in ivy.” Woven wicker mats are used to give the screens a natural look initially, until the ivy has grown all over the steel constructions. So the screens have been provided with the same detail as the garden and form a natural part of it. There is an interplay between the wind screens and the yew hedges, which are bent in the same shapes. The trees also have a role in breaking the wind. “The choice for multi-stem trees was an easy one. These forms are better suited to roof-garden planting as they are more able to withstand the wind thanks to their low centre of gravity. The pruned stems keep lines of sight open, whilst the crowns provide protection against the wind.” Species have been chosen that also form a valuable addition to the range from an ecological perspective, with abundant blossom and a rich yield of fruit.