Biodiversity on ‘The Hilltop’ Creates Natural Classroom

Lori Silvia keeps an eye on the biodiverse rain gardens she has created at St. George’s School in Middletown, R.I. (Regina DeAngelo/ecoRI News photos)

Lori Silvia keeps an eye on the biodiverse rain gardens she has created at St. George’s School in Middletown, R.I. (Regina DeAngelo/ecoRI News photos)

By REGINA DeANGELO/ecoRI News contributor

The school’s gardens are filled with native plants.

The school’s gardens are filled with native plants.

MIDDLETOWN, R.I. — “Crab grass,” she says, “is my nemesis.”

Crab grass loves heat, salt and sandy soil. But so does Asclepias tuberosa, the flower we know as milkweed, which we plant to attract monarch butterflies.

Nemesis or not, it proved small in the grand schemes of landscape designer Lori Silvia. During the past six years, Silvia has created three large-scale, biodiverse rain and pollinator gardens amid the manicured estate of St. George’s School, on Purgatory Road.

Established in 1896, St. George’s stands like a windblown Gothic castle on a hill overlooking Newport and the Atlantic Ocean. (It’s called "The Hilltop" for its views.) Among its 125 acres grow some of the most biodiverse, large-scale gardens in the state of Rhode Island, presided over by a petite landscape designer joined on her rounds by her dog Trilly.

Silvia arrived at St. George’s in 2008, to rejuvenate its surroundings and bring to life the gardens that weren’t yet there but for her vision of them. “At first,” she says, “it was just a few shrubs and a lot of mulch.”

Going past traditional landscaping, Silvia’s vision was to call forth ecologically sustainable, biodiverse native gardens that were beautiful, functional and educational — what she terms “living plant classrooms,” where students can observe the landscape evolving as the plants mature.

In 2011, she undertook a formidable project: absorb and divert all the rainwater that poured off the 4,500-square-foot Nathaniel Hill Library and its surrounding roads with a LEED-certified rain garden. Starting with site engineers’ maps, she tackled the task with flowers, shrubs and grasses — most of which were native to Rhode Island — in what would become a 1,600-square foot, biodiverse rain garden of purples, pinks and yellows that would sustain itself indefinitely without intentional watering.

To do this, Silvia chose almost all native plants that could handle both drought and inundation, and at same time support beneficial pollinators and birds. The garden features perennials such as white turtlehead and New York ironweed; cardinal flower, black pussy willow, goldenrod and Echinacea; and shrubs such as Viburnum and buttonbush.

Each of these plants had to meet at least one of the check marks on Silvia’s rain-garden criteria list: water-lover (pussy willow, swamp azalea) bird-attractor (highbush blueberry), fragrance-maker (sweet pepperbush), and pollinator (all of them). They all had to withstand the variable climate of coastal Rhode Island, and preferably be native to the state. To reach LEED certification, all of it would have to grow into an ecological system that would sustain itself within a year.

Silvia’s garden achieved “gold” certification from LEED, meeting its criteria of containing and keeping water in its place and letting it sink back into the water table, sustaining a garden that was not just a pleasure to look at but a methodically engineered drainage system.

Each of Lori Silvia’s gardens had to address specific landscape and architectural issues.

Each of Lori Silvia’s gardens had to address specific landscape and architectural issues.

Six years later, Silvia’s rain garden is still evolving as she continually cultivates, photographs and even videotapes it.

“Right after install,” she recalls, “we had a big storm. I could watch where the water was going, and then redesign.”

The school’s rain garden is tied to the sewer system and can handle an emergency overflow at 100-year-storm levels, but this, Silvia notes, is just in case of emergency.

“The plants and soil absorb all the water,” she says. “The purpose of a rain garden is to keep water on site and let it slowly permeate into the groundwater table.”

Each of St. George’s biodiverse gardens had to address specific landscape and architectural issues. One of them, which Silvia embarked on in 2015, had to serve as the aesthetic and climate buffer of the newly built academic center, a 36,000-square-foot brick building with copper-faced towers that give off heat like a giant radiator. The landscape she created comprises steep slopes, forest area, two swales and three rain gardens. Temperatures from a sheer wall of brick on the south face of the building are captured by heat-loving beach roses, and tall trees shade the building in summer while not obstructing ocean views. Sedge grass follows the slopes and captures flowing rainwater.

Hidden in the aesthetics is all the work that these gardens do. They capture, absorb or divert water to where it can be useful. Plants such as goldenrod, with its big roots, stabilize the slopes and prohibit erosion. Salt-marsh hay lining the swales checks fast-moving, salty water.

St. George’s students are invited to participate in Silvia’s landscapes. The Sustainable Project Group made a “Victorian Stumpery,” a shaded garden with tree stumps that have tiny plants growing out of the hollows. As the stumps rot, they feed the trees above them.

“When the kids come back in fall,” Silvia says, “they get to see how their work has evolved.”

Silvia’s goal is to get the students outside and appreciating the ecology of the campus.

“This is a ‘learning landscape’ where students will be encouraged to study and enjoy the outdoor environment from the open-air-lawn ‘classrooms,’” she says. “My hope is that it will become a living-plant classroom.”

Silvia’s personal life reflects her work’s balance between the wild and cultivated. An artist and gardener who grew up in a family of gardeners, she studied fine arts and went to work as a landscaper. She eventually earned a master’s degree from Harvard’s Landscape Institute. Along the way, she continuously practiced shade gardening at home in Little Compton. Those years taught her what she needed for her work at St. George’s.

“You gotta be patient, and let the plants do their job,” she says.