Gravel gardens can be a startling sight
The phrase “gravel garden” does not resonate with Jeff Epping, although he is a leading proponent of adopting this style of planting, which is beautiful and exceptionally hardy.
“I never liked the name because it just doesn’t conjure up what’s possible,” said Epping, director of horticulture at Olbrich Botanical Garden in Madison, Wisconsin, where he created his first gravel garden in 2009 and has since planted three others.
In the same way that rock gardens aren’t just about boulders, he said, gravel isn’t the main character here either. On the contrary, it plays the essential role of support. The plants – in his case, mostly native grasses and flowering perennials reminiscent of natural prairie plant communities – do the show.
“When I talk to people about gravel gardening without them seeing it, they might say, ‘Oh, that sounds interesting,'” Epping said. “But then they see the pictures and express surprise that it’s as beautiful as any garden.”
Then he adds a little extra: a gravel garden could require 80% less work to maintain than a conventional garden with similar plants.
This is how conversions happen.
It is precisely because of the gravel that maintenance is so drastically reduced. It is not just a band aid – not a layer of mulch, but a deliberate 4 or 5 inch deep foundation in which the garden is planted. This depth discourages weeds from finding a foothold, while minimizing runoff, directing available water where the roots can use it.
Caring for an established gravel garden requires even less week-to-week attention than caring for a lawn, which “might as well be a parking lot, as far as garden creatures go,” said Epping.
In 2018, he transformed the lawn in front of his house into an aquatic gravel garden. And now the time he once spent mowing is spent watching bees, butterflies or a goldfinch nibbling on a Coreopsis seed head.
A chain of inspiration
On visits to English gardens over the years, Epping had seen gravel gardening come to life, particularly in the converted car park that welcomes visitors to the nursery and gardens by Beth Chatto, in the county of Essex. the cottage in Dungeness which belonged to artist Derek Jarman is another well-known example.
For a while, Epping filed it all down. It wasn’t until he saw a smaller scale version of Roy Diblik, at Northwind Perennial Farm in Burlington, Wisconsin, that he felt called to action. And Diblik – inspired by the same images, as well as a visit to German designer Cassian Schmidt’s garden, Hermannshof – helped Epping create Olbrich’s first gravel garden.
Several states further, Andrew Bunting, vice president of public gardens and landscapes for the Pennsylvania Horticultural Society, had the same frames of reference, including Epping’s work. He had enjoyed years of regular visits to the gravel garden at Chanticleer Garden in Wayne, Pennsylvania, not far from his home in Swarthmore.
For him, the trigger that turned those inspirations into action was the pandemic.
Bunting found himself at home in 2020 in what became his “COVID office,” watching his “prairie front garden” day after day, he said, from his seat at the dining table. “I remember thinking, ‘It’s tired; it needs to be redone.
Another factor in his decision was the presence of two stubborn weeds, lesser celandine (Ficaria verna) and Star of Bethlehem (Ornithogalum umbellatum). Could they be brought under control for good by the gravel method?
Make a bed, with gravel
A good gravel garden site is flat or gently sloping and has good drainage. Although the classic images are sunny places, this is not a requirement.
At Epping, for example, in the shade of a large oak tree, a white wooden aster (Eurybia divaricata) and bigleaf aster (E.macrophylla), both native, grow in gravel. The blue-stemmed goldenrod (Solidago caesia) is happy too, as are the sedges (Sedge) and even non-native tint standards such as epimedium and Hosta.
All of the preparatory steps involve keeping the soil under the gravel, to avoid creating invitations for weed seeds to take hold. Engineering is a lot like building a raised bed – although you don’t have to raise it, but you have to dig out the top layer of soil to make room for that gravel base of 4 or 5 inches.
As in a raised bed, what is needed is a perimeter barrier – in this case, about 6 inches high – to contain the gravel to a consistent depth throughout. Otherwise, the pebbles near the edges would naturally spread out, and the finer layer of gravel would invite weeds to self-seed.
Any solid edging material – curbs, bricks, concrete pavers, or even found stones – can be used. (Wood would also work, but it will rot eventually.) An adjacent house foundation, sidewalk, or stone wall could be part of the enclosure.
Before Bunting began renovating his garden, he had an excavation contractor scrape away the top layer of soil – so the new garden was level with an existing walkway – and then bring in the gravel. The medium of choice: hard washed stone like granite or quartz, not limestone or sandstone. Epping recommends a size of 3/16 to 1/4 inch; Bunting used half inch.
Whether you excavate or not, to prepare your site for gravelling, you must remove most of the existing vegetation. A tree or shrub can stand as long as the ground is teased away from its top and upper root, which will be topped with stone.
At planting time, pint- or quart-sized plants are ideal, Epping said, because their root systems are about as deep as gravel.
Each is held over a bucket to catch any soil that comes loose from the top of the unpotted plant or falls when the roots are carefully parted.
“Planting plants with soil still on the root ball will later increase weed pressure,” Bunting said.
“The cleaner we can keep the gravel at all times, the better off we’ll be,” Epping said. To that end, he added, planting is accomplished “with gloved fingers, not trowels”.
Although established gravel gardens rarely need supplemental water except in times of drought, watering every other day is essential in the first few weeks after planting, before the loose roots enter the soil through the Pierre.
Plants that work
Multiple seasons of visual interest and adaptability to dry conditions are two qualities Epping looks for in plant selection.
Bunting also wanted to try a few slightly hardy ones: the western prickly pear hybrids (Opuntia) or South African species such as the ice plant (Delosperm) and Aloe polyphyllawhich he called “a real long shot”.
His hope? That they may prove more winter hardy if their “feet” stay dry in the gravel base, rather than in icy, muddy puddles.
Plants native to the American prairie meet Epping’s requirements. He is particularly fond of pale purple coneflower (Echinacea pallida), prairie gypsophila (Leaf spurge), foxglove beardtongue (Penstemon Foxglove) and prairie coreopsis (Coreposis palmata).
It plants densely, perhaps a foot apart, combining flowering perennials with grasses such as prairie drip (Sporobolus heterolepis) and little bluebeard (Schizachyrium scoparius), as well as some non-native bulbs. One of these stars: Allium angulosum ‘Summer Beauty’, which provides a spectacular display of lavender in midsummer and is a pollinator favorite.
By the time things grow, Epping Gardens reads like almost solid plants.
Bunting’s style is looser. Once her more recently installed garden is filled in, some gravel will intentionally remain visible. The view from the dining room is already emerging, like lush mounds of blue stars (Amsonia hubrichtii), catmint (Nepeta x faassenii Walker’s Low) and Baptisia Ivory Towers pair with purple moor grass (Molinia caerulea subsp. Arundinaceae Skyracer) and more.
The to-do list for gravel gardens isn’t just about minimizing weeding and watering chores. They are gardens that also do not require mulching or fertilizing, and their edges are already defined, so they do not need to be cut every spring as you would with a conventional bed adjacent to the lawn.
The essential: a cleaning at the end of winter or at the beginning of spring. All herbaceous plants are cut and debris carefully removed, lest the organic matter decompose to form a breeding ground for weeds.
A leaf blower comes in handy, for that big cleanup moment and anytime bits of wilted plants end up on the gravel surface – under trees, for example, where flowers or foliage have fallen.
Do you dare to let certain plants go their own way? Bunting intends to experiment with some self-seeds. And Epping is having fun, adding pockets of sand here and there to allow the volunteers – “to have a little fun”, as he put it, “with a few little experiments”.
Gravel creates a different type of garden, one that invites such creativity but involves a learning curve, even for experienced horticulturists.
“I fully admit that I’m not an expert on this, which is kind of funny,” Bunting said. “I feel like a beginner gardener in the gravel garden again.”
Roach, a freelance writer, former longtime journalist and author of garden books, is a columnist for The New York Times.