The Pinnacle at Symphony Place

By David Groleau, Piedmont Landscape

Soil depth posed a challenge, which ranged from 24-40 inches, when installing and bracing the 12 7-foot Redbud trees. To overcome this, the contractor installed custom 'pyramid' tree braces. The trees were planted and 16-gauge wire was used to secure the trees to the structures.

Piedmont Landscape delivers a first with their rooftop project, The Pinnacle at Symphony Place. Located in Nashville, Tennessee, The Pinnacle at Symphony Place is Nashville's first and only Class AA office tower. It is also the city's first LEED gold certified skyscraper. Standing 29 stories high, and boasting a 1-acre rooftop garden, it is a first-class building.

Nineteen sedum varieties, used instead of turf, made up the majority of the plantings. The sedum was specialty grown. Notice how the Redbud trees have engulfed the pyramid tree braces.

 


Besides sedum, the palette included native plants such as Evergreen Clematis, Liriope, Black-Eyed Susan and Tennessee Coneflower. With the use of these plants along with the installation of 8,000 linear feet of drip irrigation supplied by a harvesting system, demand for irrigation was reduced by 50 percent.

The project scope included the landscape and irrigation installation for the building's streetscape and rooftop garden Piedmont installed 35 trees, more than 33,000 shrubs and groundcover plants, 8,000 linear feet of drip irrigation, 75 tons of Tennessee River Slick rock, and 1,000 yards of special lightweight soil. All the plant material used was native and/or drought-tolerant.

A crane was used to lift 75 tons of Tennessee River Slick rock to the garden, taking 40 loads. The rock provided two purposes - it was installed on the perimeter to be used as a rainwater drainage system, and it was also used to break up the hardscape. The majority of the plant material reached its destination by being carried up seven flights of stairs. For the larger material, such as Redbud trees, the 100-ton crane was used. The tree and soil installation required the roadway to be closed for one week from 8 a.m. to 3:30 p.m.

The majority of this landscape installation project took place seven floors up on the one-acre rooftop garden. Besides the garden, a streetscape was also installed. Combined, more than 33,000 drought-tolerant shrubs and ground cover plantings were used.

The Pinnacle at Symphony Place located in Nashville, Tennessee is a 29-story building, and Tennessee's first LEED-certified skyscraper. The finalized landscape installation project took 1,300 hours to complete, utilizing a team of more than 10 workers, including a project manager. Rooftop garden visitors can view the Cumberland River and Tennessee Stadium. Such LEED certification was the driving focus behind the client's objective and project theme - create a sustainable, low-impact landscape that offers a healthy, invigorating and awe-inspiring environment.

The streetscape gives visitors a small taste of what is to come atop the rooftop garden and features Oaks and Elms complemented by versatile Liriope, fragrant Honeysuckle and hardy Fargesia.

The rooftop terrace garden adds beauty and integrity to the building's more than 500,000 square feet of office space and is capable of hosting outdoor events for up to 300 people. It features tall, bright orange Butterfly Weed, silvery gray Lamb Ears and 19 varieties of sedum. The Pinnacle at Symphony Place is the commercial jewel in the crown of Nashville's arts, entertainment and office district of SoBro. The results of high design and simplicity allow for tenants and guests to enjoy a healthier and more productive environment.

The completed rooftop garden utilized 12 Autumn Brilliance Serviceberry Redbuds, 278 shrubs such as fragrant Little Henry Sweetspire and dense Blue Princess Holly, 33,000 groundcover plants including multiple varieties of colorful sedums and pale blue Amsonia.

The project height posed a major challenge. First, 1,000 yards of specially designed lightweight soil were blown up seven stories through a 90-foot vertical and 200-foot horizontal vacuum. It took five full days to install the soil because it was delivered 75 yards at a time, requiring 11 truckloads.

Challenges Faced

This project had many unusual challenges that were overcome by critical thinking and the use of creative materials. The main, overlapping challenge was the height of the project, which was seven floors up. Trees, rock, soil and plant material all had to go up. A 100-ton crane was used to lift the 12 Autumn Brilliance Serviceberry Redbuds and the 75-ton load of Tennessee River Slick rock. 1,000 yards of soil were installed by the use of a 90-foot vertical and 200-foot horizontal vacuum. The project team carried the plant material up the seven flights of stairs. Street space was needed when using the crane and vacuum. Logistical planning was required to get permission to close the road. Once approved, the road was closed for one week from 8 a.m. to 3:30 p.m. All trees, soil and rock had to be installed during that tight timeframe. Other challenges included securing the specified sedum. Many of the varieties shown in the original design were not appropriate selections, so suggestions were made for more sustainable and suitable varieties. Also, all the sedum was specially grown for the project.

Finally, the depth of the soil on the rooftop garden caused a challenge when bracing the trees. A custom brace was created to secure the trees in place.