Looking north from the lawn of Tenjin Central Park, tiers of trees soften the outline of a building as they rise to the fourteenth floor. At ACROS Fukuoka, the Step Garden is more than rooftop decoration: it carries the park upward as a second piece of terrain.
The park continues onto the building
ACROS Fukuoka opened on 29 April 1995 on the former site of the Fukuoka Prefectural Office. Its south face steps down toward Tenjin Central Park, with trees and shrubs planted across the roof of each level.
The official guide places about 5,400 square metres of planting between the second and fourteenth floors. Trees are trimmed to create visual unity, making the canopy of the park appear to continue toward the top of the building.
A garden that began with 37,000 plants
After construction, 76 varieties and about 37,000 plants were installed. Further planting and seeds dispersed by wild birds increased that diversity; the facility now records around 120 varieties and 50,000 plants.
Those numbers describe a garden that did not stop when the drawings were complete. Planted trees, arriving seeds and extending branches have altered the density of the green face over more than three decades.
From a distance the terraces read as one slope. On the stairs, layers of leaves separate at each height. The canopy seen from the park and the foliage observed from the path give the same building different edges.
The entrances are on the park side
The Step Garden is entered from two points on the park side, not from inside the building. It is open from 9 a.m. to 6 p.m. from March through October and closes at 5 p.m. from November through February. It also closes in bad weather, so current notices matter.
The rooftop observation deck opens from 10 a.m. to 4 p.m. on weekends and public holidays. Rather than treating the summit as the only destination, pause where the height of the park and the building begin to exchange places.
Rain and strong sun change both the stone steps and the leaves. Staying on the path, look at shade, trunks and the direction of drainage. The details reveal how a roof garden lives under conditions unlike a bed at ground level.
Leaf shade reaches the temperature of the city
Citing research by Kyushu University, the facility says cool air generated by the Step Garden at night makes the garden and neighbouring park comparatively cooler than the surrounding city. The planting works on the air around it as well as on the view.
The green slope from the park, the leaves beside the stairs and the cool air descending at night are not separate effects. They form one landscape because plants have rooted across the building and changed with time.
On the south face of ACROS Fukuoka, the boundary between building and garden disappears into the canopy. The idea of growing the park to the fourteenth floor is still being revised by pruning, arriving seeds and each season’s leaves.