The task for anyone who designs a garden: “We predict the future – we see what is not there.”
That’s how Ethan Kauffman, the director (and leading fortune teller) of Stoneleigh, a public garden that opened five years ago on a historic estate in Villanova, Pennsylvania, puts it.
The point is that gardeners also need to see what is over there. In the case of the 42-acre Stoneleigh, including seven acres of pachysandra, when Mr. Kauffman first saw the property nearly seven years ago.
In any context, a sea of what was once a go-to groundcover—what turned out to be one of ornamental horticulture’s ubiquitous invasive plants—would be overwhelming. But Mr. Kauffman, the former director of South Carolina’s Moore Farms Botanical Garden, was hired to fulfill a mission that makes it even more challenging.
He is guided by what he calls the “conservation ethos” of Stoneleigh’s parent organization, Natural Lands, a non-profit organization that currently cares for more than 23,000 acres in eastern Pennsylvania and southern New Jersey – in 42 nature preserves and in Stoneleigh – and has retained more than 135,000 acres over its history, since the 1950s.
To complicate matters, every garden feature he envisions must somehow complement the backdrop of a Philadelphia Main Line estate, with its 17,000-square-foot Tudor Revival stone mansion and massive, century-old stone pergola.
Can an ecologically oriented landscape of native plants be integrated in such a place? The answer from Natural Lands and the horticultural team at Stoneleigh is a resounding yes.
First things first
When Mr. Kauffman arrived, there hadn’t been a garden on the property for more than four years, other than basic things like mowing. Where to start?
His crew — which has only five full-time members and one seasonal gardener — took to some of the pachysandra-infested acres. (The current score: two down, five to go.) However, they knew it would be easy to fall into that forest-before-the-trees trap and get distracted by the obvious when it’s less urgent . So they emphasized higher value tasks. Their list of priorities would be a good roadmap for starting or revamping a garden of any size or purpose.
First, they identified a number of key areas to focus on in the early stages, establishing their greater intent — an early statement that looks ahead to longer-term goals.
Also critical, in self-defense: any bare ground is an invitation to weeds and will require many hours of maintenance if left uncultivated. So they planted blanks as soon as possible.
Third, where trees and shrubs were part of the final plan, they knew they had to get them in the ground. This was especially urgent with the natives Mr. Kauffman had specified for the remodeled landscape, many of which were new or unusual to the nursery trade and only available in small sizes. The time spent waiting for the payout would be extra long.
Identifying key areas for maximum impact was easy: The parking lot would make the first impression on all visitors — currently about 40,000 a year, open for free Tuesday through Sunday, except Thanksgiving and Christmas.
But there lived about an acre of pachysandra. Ten dumper loads were displaced in favor of combinations such as pink flowering dogwoods (Cornus florida Cherokee Brave) underplanted with golden ragwort (Packera aurea). The yellow flowers of the ragwort coincide with the spring blooms of the trees, creating a friendlier welcome mat.
The main building, formerly the home of the Haas family, was another major destination. It needed some botanical clarification, as did the majestic 220-foot pergola. Grass grew under the pergola, not the perennial beds Mr. Kauffman envisioned. It begged for vines to scramble up and over as well.
“The pergola is really charismatic,” he said. “We thought this was something that if we could do a small portion — and hopefully do a good job with it — it would give visitors an idea of what was to come.”
He also added that it was “an opportunity to showcase a lot of native vines that people may not be using.”
Today, 24 species of native vines climb the pergola, including the less mature yellow passionflower (Passiflora lutea) and a domestic subspecies of hops (Humulus lupulus ssp. americanus), the female flowers clustered in small green, pinecone-like structures. Small-flowered clematis share the property, along with a Victorian favorite loved for its giant leaves and the curious, hidden flowers that inspired its common name, Dutchman’s pipe (Aristolochia macrophylla).
On another upright pergola, prairie rose (Rosa setigera) has already reached 20 feet. There is also training to transform lampposts on the site into flowering columns.
Select varieties of the more familiar trumpet honeysuckle (Lonicera sempervirens) and trumpet creeper (Campsis radicans) are also making a big splash, along with American wisteria (Wisteria frutescens) — not the invasive Chinese species.
A design trick with the honeysuckle and trumpet creepers: “We plant them in clusters of three,” Mr. Kauffman said, “with a red, yellow and orange variety all in the same hole, to create these colorful bursts.”
Some home gardens don’t have such a vertical structure, but that doesn’t necessarily mean there are no vines.
“People say, ‘I like wisteria, but I can’t put it in my garden,'” Mr. Kauffman said. “And I’m like, ‘Well, yes, you can. You can treat it like a bush.'”
Once in the ground, the young one-gallon plants are staked, then pruned immediately after flowering, and then again every year later, if necessary.
The woodvamp (Decumaria barbara) is treated the same way — and can double as a ground cover.
“I just look at plants and I think, ‘What are the possibilities?'” said Mr. Kauffman. “And we are experimenting with it. That’s what we do as gardeners, right? We’re just having fun.”
Trees with a difference, hedges with intention
Mr. Kauffman explores versatility – and not just with vines. The pergola plantings include trees such as weeping yellowwood (Cladrastis kentukea White Rain) that are pruned to train it.
The skeletons of two venerable dead trees – an English yew (Taxus baccata) and a London plane (Platanus x acerifolia) – were not erased, but turned into prominent sculptures. Others were left as snags, or trees for wildlife, host bird and mammal families, supporting more native vines.
On the stone walls of the mansion are eastern redbud (Cercis canadensis) and boxwood elderberry (Acer negundo) espaliers, anchored by eye hooks screwed into the mortar, as well as more vines and shrubs.
Witch hazel (Hamamelis virginiana), particularly showy lemon lime, inhabits one wall. “It’s this crazy, variegated green-and-yellow selection that looks like something out of ‘The Matrix,’ but it’s pretty eye-catching,” Mr. Kauffman said.
On the large, canopied stone gates, or lychgates, the white-flowered weeping oriental redbud Vanilla Twist is looped around the posts like a vine. “We prune all the side branches,” he said, “and just let it do its job.”
When he got to Stoneleigh there weren’t really any hedges. “Most of the experience was just this open-ended kind of journey,” he said. “You didn’t really have anything separating it or creating visual barriers, and we knew that would be important later on.”
A fine example is a row of dwarf teddy bear southern magnolias (Magnolia grandiflora). White pines (Pinus strobus) teams with American arborvitae (Thuja occidentalis Smaragd) in another hedge, with a lone gold-foliated Yellow Ribbon arborvitae lining up, clamoring for attention.
Shrubs that grow in hedges include ragwort (Baccharis halimifolia), hearts-a-bustin’ (Euonymus americanus) and an obscure native upland swamp privet (Forestiera ligustrina), “a great replacement for our non-native privet,” said Mr. Kauffman. , referring to another serious invasive.
“And we have this crazy wildlife hedge with 70 different species of native woody plants, in a double row,” he said. “It’s 200 feet long, about eight feet high. We have vines and perennials there – it’s kind of a dynamic thing.
Cover a piece of ground
The hedges are just one “feature for care,” Mr. Kauffman said, a sign that this is a garden—though less conventional than its predecessor.
The team’s approach to what was once 14 acres of mowed grass is another hint.
“We’ve had at least half of it mowed and it looks so nice,” said Mr. Kauffman. “We mow the edges — the first six feet — so you can see we’re taking care of it, but the rest we just let grow tall.”
Fewer weeds is another sign of human intervention. Living ‘green mulch’, in the form of ground covers, is the main tool in Stoneleigh’s campaign against them.
Golden ragwort provides good cover against unwanted species, as does barren strawberry (Geum fragarioides, formerly Waldsteinia). Sedges (Carex), Canadian ginger (Asarum canadense) and creeping phlox (Phlox stolonifera) are other potent partners in this bare-soil weed control effort.
“As a small staff, you just have to find a way,” Mr. Kauffman said. “And we are experimenting: with bare, weedy areas where we are tired of pulling, we only plant Parthenocissus. And in a year we will no longer have to deal with it.”
That may surprise gardeners who too often pull up Virginia creeper (Parthenocissus quinquefolia) or scrub (P. inserta), native vines that are often misunderstood despite their high natural value and brilliant fall color.
Could we change our way of thinking and incorporate them into our garden plans? That depends on our way of looking – on how we visualize the way forward.
Margaret Roach is the creator of the website and podcast A way to gardenand a book of the same name.
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