The phrase “gravel garden” doesn’t resonate with Jeff Epping, although he’s a leading proponent of adopting this planting style, which is beautiful and exceptionally resilient.
“I’ve never liked the name, because it just doesn’t conjure the look of what’s possible,” said Mr. Epping, the director of horticulture at Olbrich Botanical Gardens, in Madison, Wis., where he created his first gravel garden in 2009, and has planted three more since.
In the way that rock gardens aren’t all about the rocks, he said, gravel isn’t the lead character here, either. Rather, it plays the essential supporting role. The plants — in his case, mostly native grasses and flowering perennials evocative of natural prairie plant communities — do the showing off.
“When I tell people about gravel gardening without them seeing it, they might say, ‘Oh, that sounds like it might be interesting,’” Mr. Epping said. “But then they see the images, and express surprise that it’s as beautiful as any garden.”
Then he adds a kicker: A gravel garden could be 80 percent less work to maintain than a conventional garden with similar plants.
That’s how converts are made.
It is precisely because of the gravel that upkeep is so drastically reduced. This is no mere top-dressing — not a mulch layer, but a deliberate foundation four or five inches deep that the garden is planted into. That depth discourages weeds from finding a foothold, while minimizing runoff, directing available water to where roots can use it.
Caring for an established gravel garden requires even less attention week to week than taking care of a lawn, which “might as well be a parking lot, as far as the garden’s creatures go,” Mr. Epping said.
He turned the grassy stretch in front of his home into a water-wise gravel garden in 2018. And now the time he once spent mowing is devoted to watching bees, butterflies or a goldfinch nibbling at a Coreopsis seed head.
A Chain of Inspiration
On visits to English gardens over the years, Mr. Epping had seen gravel gardening brought to life, particularly in the transformed parking area that welcomes visitors to the nursery and gardens made by Beth Chatto, in the county of Essex. The cottage at Dungeness that belonged to the artist Derek Jarman is another well-known example.
For a time, Mr. Epping filed all of that away. It wasn’t until he saw a smaller-scale version by Roy Diblik, at Northwind Perennial Farm in Burlington, Wis., that he felt called to action. And Mr. Diblik — inspired by the same images, as well as a visit to the German designer Cassian Schmidt’s garden, Hermannshof — helped Mr. Epping make Olbrich’s first gravel garden.
Several states away, Andrew Bunting, the vice president of public gardens and landscapes for the Pennsylvania Horticultural Society, had the same frames of reference, including Mr. Epping’s work. He had enjoyed years of regular visits to the gravel garden at Chanticleer Garden in Wayne, Pa., not far from his Swarthmore home.
For him, the trigger that turned those inspirations into action was the pandemic.
Mr. Bunting found himself at home in 2020 in what became his “Covid office,” looking out at his “meadow-ish front garden” day after day, he said, from his seat at the dining table. “I remember thinking, ‘This is tired; it needs redoing.’”
Another factor in his decision was the presence of two tenacious weeds, lesser celandine (Ficaria verna) and star of Bethlehem (Ornithogalum umbellatum). Could they be subdued for good by the gravel method?
Making a Bed, With Gravel
A good gravel garden site is level or a gentle slope, and has decent drainage. Although the classic images are of sunny spots, that is not a requirement.
At Mr. Epping’s home, for instance, in shade cast by a big oak, white wood aster (Eurybia divaricata) and the big-leaved aster (E. macrophylla), both natives, grow in the gravel. The blue-stemmed goldenrod (Solidago caesia) is happy, too, as are sedges (Carex) and even nonnative shade standards like Epimedium and Hosta.
All the preparatory steps are about keeping any soil below the gravel, to avoid creating invitations for weed seeds to take hold. The engineering is a little like building a raised bed — although you don’t have to actually raise it, but you do have to excavate the top soil layer to make room for that four- or five-inch gravel base.
As in a raised bed, what is required is a perimeter barrier — in this case, about six inches high — to contain the gravel at a consistent depth throughout. Otherwise, pebbles near the edges would naturally spread out, and the thinner layer of gravel would invite weeds to self-sow.
Any solid edging material — curb stones, bricks, concrete pavers or even found stones — can be employed. (Wood would also work, but it will eventually rot.) An adjacent house foundation, sidewalk or stone wall could form part of the enclosure.
Before Mr. Bunting began his garden makeover, he had an excavating contractor scrape away the top layer of soil — so the new garden would be level with an existing walkway — and then bring in the gravel. The medium of choice: washed hard stone like granite or quartz, not limestone or sandstone. Mr. Epping recommends three-sixteenths to quarter-inch size; Mr. Bunting used half-inch.
Whether you excavate or not, to make your site gravel-ready you must remove most of the existing vegetation. A tree or shrub can remain as long as the soil is teased away from its crown and upper root area, which will be topped with stone.
At planting time, pint- or quart-size plants are ideal, Mr. Epping said, because their root systems are about as deep as the gravel. Each one is held over a bucket to catch the soil that comes off the top of the unpotted plant or that is shed when the roots are carefully teased apart.
“Planting plants with soil still on the root ball will, down the road, add to weed pressure,” Mr. Bunting said.
“The cleaner we can keep the gravel at all times, the better we will be,” Mr. Epping concurred. To that end, he added, planting is accomplished “with gloved fingers, not trowels.”
Although established gravel gardens rarely need supplemental water except during drought, watering every couple of days is essential in the first weeks after planting, before the loosened roots make their way down through the stone into the soil.
Plants That Work
Multiple seasons of visual interest and an adaptability to dry conditions are two qualities Mr. Epping seeks in plant choices.
Mr. Bunting also wanted to try some marginally hardy ones: Western prickly pear cactus hybrids (Opuntia) or South African species like ice plant (Delosperma) and Aloe polyphylla, which he called “a real long shot.”
His hope? That they may prove extra winter-proof if their “feet” stay dry in the gravel base, rather than in icy, mucky puddles.
Native plants of the American prairie fit Mr. Epping’s requirements. He is especially fond of pale purple coneflower (Echinacea pallida), prairie baby’s breath (Euphorbia corollata), foxglove beardtongue (Penstemon digitalis) and prairie coreopsis (Coreposis palmata).
He plants densely, maybe a foot apart, combining the flowering perennials with grasses like prairie dropseed (Sporobolus heterolepis) and little bluestem (Schizachyrium scoparium), along with a few nonnative bulbs. One such star: Allium angulosum Summer Beauty, which offers a dramatic lavender display in its midsummer moment and is a pollinator favorite.
By the time things grow in, Mr. Epping’s gardens read as nearly solid plant.
Mr. Bunting’s style is looser. Once his more recently installed garden fills out, some gravel will intentionally remain visible. The view from the dining room is already shaping up, as lush mounds of bluestar (Amsonia hubrichtii), catmint (Nepeta x faassenii Walker’s Low) and Baptisia Ivory Towers consort with purple moor grass (Molinia caerulea subsp. arundinacea Skyracer) and more.
A Minimum of Maintenance
The don’t-need-to-do list for gravel gardens is not just about reduced weeding and watering duties. These are gardens that don’t require mulching or fertilizing either, and their edges are already defined, so they needn’t be cut each spring the way you would with a conventional bed adjacent to lawn.
The essential routine: a late-winter or early spring cleanup. All the herbaceous plants are cut back, and the debris carefully removed, lest that organic matter break down to form a weed-inviting medium.
A leaf-blower is helpful, for that big cleanup moment and whenever fading bits of plants find their way onto the gravel surface — under trees, for example, where blooms or foliage have fallen.
Do you dare to allow some plants to have their own way? Mr. Bunting intends to experiment with some self-sowns. And Mr. Epping is dabbling, adding sandy pockets here and there to allow volunteers — “fooling around a little,” as he put it, “with some small experiments.”
Gravel makes for a different kind of garden, one that invites such creativity, but involves a learning curve, even for experienced horticulturists.
“I fully admit I am not an expert at this, which is actually kind of fun,” Mr. Bunting said. “I feel like a beginning gardener again in the gravel garden.”