No plant is an island: Think of plant groups, not specimens
Are your plants looking lonely, surrounded by small patches of high-maintenance bare soil? If they look like they’re suffering in solitary confinement, maybe they are.
Many plant and landscape experts have begun thinking of plants in terms of communities, instead of as individual specimens. They recommend that home gardeners look to the wild for inspiration.
“Thinking of plants in terms of masses and groupings, as opposed to objects to be placed individually in a sort of specimen garden, is what most young people are really responding to now,” says Brian Sullivan, vice president for landscape, gardens, and outdoor collections at the New York Botanical Garden.
The shift in landscaping toward looking at plants as interrelated species gained prominence almost a decade ago with the opening of the High Line, a public park built along an old elevated rail line in New York City, Sullivan says. In a move considered radical at the time — but replicated in parks and gardens across the country since then — the designers of the High Line went with a wilder look, with plantings resembling roadside grasses and wildflowers more than a traditional garden.
Many horticulturalists and landscapers say such gardens — with consideration of how plants benefit each other, and birds, insects and other wildlife — look better for more of the year, and are more functional and self-sustaining.
For landscape designer Thomas Rainer, co-author of “Planting for a Post-Wild World: Designing Plant Communities for Resilient Landscapes” with Claudia West (Timber Press, 2015), his epiphany began when he pulled over to the side of a road one day and really looked at what was growing naturally there.
“I’d been puzzling over how we can reach this holy trinity of beauty, low maintenance and functionality in landscaping. Looking more carefully at this weedy neglected patch at the side of road, I saw that it was way more biodiverse than I’d ever dreamed. I counted 23 species in just one tiny section. It was kicking my garden’s butt in terms of biodiversity,” says Rainer, who has designed landscapes for the U.S. Capitol grounds, the Martin Luther King Jr. Memorial and the New York Botanical Garden, as well as gardens from Maine to Florida.
“If you look at the way plants grow naturally, it’s completely different from the way they grow in most parks and gardens,” he says. “If you look at functioning communities of plants, they really maintain themselves.”
“We have this peculiarly American habit of adding 2 or 3 inches of mulch a couple times a year, but green mulch — ground cover — happens naturally if we let it,” he says.
He reminds home gardeners that “there’s a huge range of self-spreading, less-sexy plants that create the conditions for stability for the upright plants, and require almost no maintenance whatsoever.”
Aesthetically, too, the right ground cover adds dimension to the more dramatic plants around it, making a landscape visually interesting throughout the year, he points out.
Those interested in adopting this approach can start by seeing bare soil as the enemy.
“There isn’t much bare soil at all in the wild,” Rainer points out. “Every inch is covered and there are various levels of plants all packed in together.”
He recommends getting on your knees and examining your garden from a rabbit’s perspective, then planting the bare patches with groundcover, ideally native, like sedges or even low perennials, many of which do well in the kind of dry, shaded areas that tend to be where the bare patches are found.
“There’s been a huge rise in popularity of sedges, which come in a range of colors like icy blues or apple greens that can really set off the bright pinks of an azalea,” he says.
Sullivan, at the New York Botanical Garden, says that “with the style we’re talking about, the plants are in interconnected masses, so they are functioning communities sharing the same space.”
“One could be a trillium, a spring flower that somebody might see in March or April. When that finishes, somebody might see a fern or a carex,” he says. “Each plant takes the place of another during different seasons, so there’s never an empty moment. When the ephemerals finish, the perennials start to come up, the grasses, the sedges. And something else might come up in the late part of the season. So there’s a sequence. The garden changes but the gardener only does the job once, by the planting.”
Another fun thing to do is to step back and let the plants seed themselves for a season, Sullivan says. “Just watch and see what pops up, as opposed to planting every season.”