AECOM Roof Garden: From Corporate Garden to Nature Space Advocacy, Part 2

by Lee Parks, International ASLA, and LIAO Jingjing

An AECOM employee waters the new containers in early summer. / image: courtesy of Lee Parks, AECOM

This is the second installment in a three-part series on the evolution of AECOM’s green roof in Shanghai. Click here for Part 1, published last week.

As the plants established during the comfortable spring weather, employee engagement was high. The increase in flowers saw a direct increase in visiting pollinators, mostly bees. Flowers and foliage added visual amenity of the space, with ornamental grasses and flowers combining to create a vibrant display. Employee photo sharing on social media celebrated the beauty to be found in nature, recording wildlife spotted and seasonal highlights. The garden supported a ‘Wellbeing At AECOM’ campaign by encouraging employees to relax and enjoy contact with nature. Friends and families joined in the maintenance and watering. By June the salad and herb garden was productive and bearing results to be enjoyed.

All appeared well until the fiery and crushing July heat became a challenge for gardeners and the garden. Employee engagement quickly faded and only the core Roof Garden Committee members sustained interest to maintain and monitor plants. With no automatic irrigation system, the containers relied on employees to hand water with watering cans or a hose during dry periods.

Summer flowers attracting pollinators, including *Achillea sibirica*. / image: courtesy of Lee Parks, AECOM

*Hemerocallis fulva* / image: courtesy of Lee Parks, AECOM

*Salvia guaranitica* / image: courtesy of Lee Parks, AECOM

The impact of the summer heat on plants with high water requirements (notably in the vegetable garden containers) saw wilting and the onset of pests and disease, leading to plant losses. Volunteers to maintain plants continued to reduce and gradually the resilient species able to tolerate Shanghai’s harsh summer and seasonal typhoons came to dominate the containers. During this time the over-sized plant pots were upgraded in metallic veneer and included a shelf inside the pot rim for cups and glasses for more casual events.

By 2019 interest continued to decline and management of the roof garden was increasingly taken over by building property management. In the spring semester of 2019 Lee Parks took on a guest teaching role at Shanghai’s Tongji University as part of a Campus Rooftop Landscape design studio and during the teaching used AECOM’s roof garden as a case study for students to visit.

Sharing lessons learned with Tongji University / image: courtesy of Lee Parks, AECOM

Tongji University students visit the roof garden / image: courtesy of Lee Parks, AECOM

During the latter half of 2019, after another harsh summer, the continued exposure to sun, rain, and wind led to deterioration of furniture and some areas of decking. Senior management changes at AECOM led to fewer happy hours and social events taking place on the roof in 2019.

Scenes from the roof terrace in 2019 with *Salvia uliginosa* contrasting to the fine ornamental grass *Stipa tenuissima*. / image: courtesy of Lee Parks, AECOM

*Echinacea purpurea* / image: courtesy of Lee Parks, AECOM

Roof garden in summer typhoons / image: courtesy of Lee Parks, AECOM

At the start of 2020 the emergence of COVID-19 and a subsequent office closure led to a decline in roof garden use. After the first wave of the pandemic when employees were permitted to return to work, many used the roof terrace to socially distance, enjoy fresh air, or eat lunch away from the indoor pantry spaces, particularly during the pleasant spring seasonal weather.

Spring flowers and fresh green leaves bring a sense of renewal and hope and during this time, a demonstration ‘green roof’ box section was installed to illustrate how roof system parts come together. This ‘living cross section’ enabled clients and visitors to see the drainage cell system, soil, plant roots, and plant species for 300mm- and 600mm-deep green roof systems. It was planted with a mix of exotic, native, and wild plants collected from seed including Celosia spicata and Leonurus sibiricus. Whilst often considered as aggressive weedy species, the flowers attract a wider range of pollinators. It was around this time more species of wildlife were spotted on the roof including snails, slugs, centipedes, spiders, grasshoppers, dragonflies, and lady bugs.

‘Living cross section’ illustrating a 300mm- and 600mm-deep green roof system / image: courtesy of Lee Parks, AECOM

*Celosia argentea* / image: courtesy of Lee Parks, AECOM

*Leonurus sibiricus* mixed with *Verbena bonariensis* / image: courtesy of Lee Parks, AECOM

The impacts of the pandemic on the economy and businesses also affected employee retention, with some employees moving back to hometowns or requesting to work from home more frequently. As the roof garden started to diversify in terms of plants and wildlife, this inspired a second round of revitalization, to further increase plant diversity and repair or replace facilities to provide more benefit to employees.

Click here for the next post in the series to learn about the next stage of the green roof’s revitalization, more recent updates, and lessons learned over the course of the project.

Lee Parks, International ASLA, is a British landscape architect and Executive Director at AECOM, based in Shanghai. His research focuses on ecological landscape planning, green infrastructure, Nature-based Solutions, and ecological planting design.

LIAO Jingjing, Master, is a landscape designer at AECOM. Her research focuses on green infrastructure, Nature-based Solutions, and community renewal and empowerment.