More than 900 plants thrive in a Chestnut Hill garden that grows above 12 inches of coal

Janet Novak handed a visitor what appeared to be a lump of coal and related how “a challenge became an opportunity.”

In 2004, Novak and her husband, Chris Sarnowski, purchased an 1860s home on an eighth of an acre in Chestnut Hill.

Eager to garden, they tried to plant a Chinese tree peony in the back yard but hit rock. They discovered that four inches below the soil were 12 inches of coal slag, a by-product of coal-burning furnaces. The slag had been used as fill under what, years ago, was a taxi service garage and driveway on the property.

Novak and Sarnowski realized why the acid-loving rhododendron and azalea the previous owners planted were doing poorly. The slag made the soil too alkaline.

Novak was undeterred. She could not grow rhododendron and azalea but by adding soil, compost, and mulch, she created a thriving environment for 930 different plants in a garden her green-thumbed friends call “a jewel box.”

Although her garden peaks in May and June, something is in bloom year round. Snowdrops have bloomed every winter, she said, except in 2015 when the weather was too harsh.

Novak, a scientific editor with a master’s degree in molecular biology, has a spreadsheet for the garden listing scientific and common names for every plant.

In mid-April the garden is abloom with pink helleborus, red and pink tulips, and daffodils in shades from cream to apricot.

Hens and chicks, donkey tail spurge, creeping snapdragons, dianthus, and moss phlox colored purple, pink, white, and shades of green, spill from the crevices of the rock wall spanning the front of the property.

The wall was constructed by Fran Hammond and his crew from Morning Dew Stonework & Landscape in North Wales. Novak jammed soil between stone slabs as the wall was being constructed. The workers did not mind the intrusion, she said. They were excited to be a part of her project.

Above the wall, tall crimson hybrid tulips and burgundy “Outspoken” irises grow alongside bright yellow Japanese forest grass. Novak’s mother dug up the pink and white trillium from the woods in West Virginia, where Novak spent part of her childhood.

When she and her husband bought the stucco farmhouse, the front yard was lawn and three Bradford pear trees.

The couple cut down the trees. Now, the only lawn on the site separates flower beds filled with gravel or pine needles. The space was laid out by landscape designer Eric Sternfels of Philadelphia.

Novak cuts the lawn with a push mower. Sarnowski edges the grass along the beds with the string trimmer. He leaves garden cultivation to his wife. ”I provide the muscle,” he said.

The compost bin in the corner of the garden was a birthday gift from Sarnowski to Novak.

A gravel patio features a table and chairs and three planters filled with bog plants such as Venus flytraps and cranberries.

Later in the season, clematis will grow up a trellis, and Allegheny vine will wrap around a tupelo tree.

Because the garden is small, plants share space. When the daffodils by the back fence fade, they will be replaced with tomato plants and herbs.

Novak grows some plants from seeds like the spreading wild red columbine. She swaps plants and information with other members of the Delaware Valley Chapter of the North American Rock Garden Society. Forty percent of her plants are native, but she likes the diversity of nonnative plants.

Even in winter, she is outside pruning, mulching, and weeding. Though the property is sunny, Novak said she doesn’t have to water a lot unless there is a drought. She has a rain barrel from the Philadelphia Water Department’s Rain Check Program and picks up free mulch from the Fairmount Park Organic Recycling Center.

Even the self-described “nerdy gardener” cannot grow everything to her precise specifications.

The dwarf redbud Novak planted ”was only supposed to grow to four or five feet,” she said. Instead, the tree has grown to nine or 10 feet and would be taller if not for her aggressive pruning.

This spring, the redbud, with its extra branches of deep purple and magenta blossoms, was exquisitely beautiful.

Do you have a beautiful garden? Nominate your garden by email (and send some digital photographs) at properties@inquirer.com.