Education article

Weeds to Know

The following are a selection of “weedy” native species broken out by potential benefit or use. The goal of these lists is to provide insight about plants that might be worth preserving rather than eradicating and how to utilize their value.

Weeds with Large or Showy Flowers

• Achillea millefolium – Yarrow
• Ageratina altissima – White Snakeroot
• Asclepias syriaca – Common Milkweed
• Calystegia sepium – Hedge Bindweed
• Bidens sp. – Beggarticks sp.
• Campsis radicans – Trumpet Creeper
• Erigeron annuus complex – Annual Fleabane complex
• Eupatorium serotinum – Late Boneset
• Euthamia graminifolia – Grass-leaved Goldenrod
• Nuttalanthus canadensis – Old-field Toadflax
• Oenothera biennis complex – Common Evening-primrose Complex
• Potentilla canadensis/simplex – Cinquefoil sp.
• Prunella vulgaris – Self-heal
• Robinia pseudoacacia – Black Locust
• Solidago canadensis complex – Canada Goldenrod complex
• Solidago rugosa – Rough Goldenrod
• Symphyotrichum lanceolatum – Panicled Aster
• Symphyotrichum pilosum – Old-field Aster
• Symphyotrichum racemosum – Small White Aster
• Triodanis purpurea – Clasping Venus’s looking-glass
• Viola sororia complex – Common Blue Violet complex

Weeds for Lawn Diversity

• Achillea millefolium – Yarrow
• Aristida oligantha – Prairie Threeawn
• Dichondra carolinensis – Carolina Ponysfoot
• Euphorbia maculata – Spotted Spurge
• Hydrocotyle sp. – Marshpennywort sp.
• Juncus tenuis – Path Rush
• Lobelia inflata – Pukeweed
• Nuttalanthus canadensis – Old-field Toadflax
• Oxalis sp. – Yellow Sorrels sp.
• Phyla lanceolata/nodiflora – Frogfruit sp.
• Plantago rugelii – American Plantain
• Plantago virginica _ Virginia Plantain
• Potentilla canadensis/simplex – Cinquefoil sp.
• Prunella vulgaris – Self-heal
• Symphyotrichum racemosum – Small White Aster
• Triplasis purpurea – Purple Sandgrass
• Viola sororia complex – Common Blue Violet complex

Weeds for Green Mulch

• Achillea millefolium – Yarrow
• Aristida oligantha – Prairie Threeawn
• Clinopodium vulgare – Wild Basil
• Dichondra carolinensis – Carolina Ponysfoot
• Euphorbia maculata – Spotted Spurge
• Geranium robertianum – Herb Robert
• Geum canadense – White Avens
• Hydrocotyle sp. – Marshpennywort sp.
• Juncus tenuis – Path Rush
• Lobelia inflata – Pukeweed
• Nuttalanthus canadensis – Old-field Toadflax
• Oenothera laciniata – Cut-leaved Evening Primrose
• Oxalis sp. – Yellow Sorrels sp.
• Phyla lanceolata/nodiflora – Frogfruit sp.
• Pilea pumila – Clearweed
• Plantago rugelii – American Plantain
• Plantago virginica _ Virginia Plantain
• Potentilla canadensis/simplex – Cinquefoil sp.
• Triodanis purpurea – Clasping Venus’s looking-glass
• Viola sororia complex – Common Blue Violet complex

Weeds for Understory Herb Layer

• Acalypha rhomboidea complex – Three-seeded Mercury complex
• Ageratina altissima – White Snakeroot
• Apocynum sp. – Dogbane sp.
• Clinopodium vulgare – Wild Basil
• Dennstaedtia punctilobula – Hay-scented Fern
• Geranium robertianum – Herb Robert
• Geum canadense – White Avens
• Hackelia virginiana – Virginia Stickseed
• Juncus tenuis – Path Rush
• Lobelia inflata – Pukeweed
• Oxalis sp. – Yellow Sorrels sp.
• Parthenocissus quinquefolia – Virginia Creeper
• Persicaria virginiana – Jumpseed
• Phryma leptostachya – Lopseed
• Phytolacca americana – Pokeweed
• Pilea pumila – Clearweed
• Pteridium aquilinum – Bracken
• Solidago canadensis complex – Canada Goldenrod complex
• Solidago rugosa – Rough Goldenrod
• Symphyotrichum lanceolatum – Panicled Aster
• Symphyotrichum racemosum – Small White Aster
• Potentilla canadensis/simplex – Cinquefoil sp.
• Viola sororia complex – Common Blue Violet complex

Edible and Medicinal Weeds

• Achillea millefolium – Yarrow
• Asclepias syriaca – Common Milkweed
• Clinopodium vulgare – Wild Basil
• Cyperus esculentus – Yellow Nutsedge
• Lobelia inflata – Pukeweed
• Oenothera biennis complex – Common Evening-primrose Complex
• Oxalis sp. – Yellow Sorrels sp.
• Phytolacca americana – Pokeweed
• Plantago rugelii – American Plantain
• Plantago virginica _ Virginia Plantain
• Pteridium aquilinum – Bracken
• Prunella vulgaris – Self-heal
• Robinia pseudoacacia – Black Locust
• Urtica dioica – Stinging Nettle
• Viola sororia complex – Common Blue Violet complex
• Vitis sp. – Grape sp.

Weeds for Pollinators

• Achillea millefolium – Yarrow
• Ageratina altissima – White Snakeroot
• Agrimonia sp. – Agrimony sp.
• Asclepias syriaca – Common Milkweed
• Bidens sp. – Beggarticks sp.
• Campsis radicans – Trumpet Creeper
• Clinopodium vulgare – Wild Basil
• Erigeron annuus complex – Annual Fleabane complex
• Eupatorium serotinum – Late Boneset
• Euthamia graminifolia – Grass-leaved Goldenrod
• Geum canadense – White Avens
• Nuttalanthus canadensis – Old-field Toadflax
• Oenothera biennis complex – Common Evening-primrose Complex
• Oenothera laciniata – Cut-leaved Evening Primrose
• Parietaria pensylvanica – Pennsylvania Pellitory
• Parthenocissus quinquefolia – Virginia Creeper
• Phyla lanceolata/nodiflora – Frogfruit sp.
• Potentilla canadensis/simplex – Cinquefoil sp.
• Prunella vulgaris – Self-heal
• Robinia pseudoacacia – Black Locust
• Solidago canadensis complex – Canada Goldenrod complex
• Solidago rugosa – Rough Goldenrod
• Symphyotrichum lanceolatum – Panicled Aster
• Symphyotrichum pilosum – Old-field Aster
• Symphyotrichum racemosum – Small White Aster
• Viola sororia complex – Common Blue Violet complex

Articles for the Connecticut College Arboretum Bulletin

Larry Weaner and LWLA designer Jenna Webster contributed to the 44th volume of the Connecticut College Arboretum Bulletin series.  Jenna wrote the introduction to the Bulletin and Larry’s article “Reflecting on New Directions in the American Landscape” explored existing and new directions for ecology-based design.

Select presenters from the 2019 New Directions in the American Landscape conference (founded by Larry Weaner) also contributed, including: Chad Adams of Ground Plan Studio, author and photographer Rick Darke, landscape architect and scholar Kofi Boone, and Thomas Woltz, Thomas Baker, and Jeffrey Longhenry of Nelson Byrd Woltz Landscape Architects.

Check out the Bulletin.

Cover image by Max Touhey of the Memorial Meadow in the Naval Cemetery Landscape in Brooklyn, NY.  Landscape architects: Nelson Byrd Woltz, meadow design: Larry Weaner Landscape Associates.

The Education of a Wild Landscape Designer

Larry Weaner and Tom Christopher co-authored an article for Wild Seed, an annual publication of the Wild Seed Project, a non-profit dedicated to ethical collection of wild and uncultivated forms of native plants and promotion of native plant populations.  Visit Wild Seed and their beautiful magazine.

Garden Revolution: How Our Landscapes Can Be a Source of Environmental Change

Larry’s book Garden Revolution: How Our Landscapes Can Be a Source of Environmental Change, co-authored with writer Tom Christopher, was released by Timber Press in May 2016.  Visit the book’s page on Timber Press.

An Ecological Perspective for the Connoisseur Conifer Collector

By Larry Weaner & Jenna Webster

(First appeared in Conifer Quarterly, Summer 2010. Photos by Larry Weaner unless indicated otherwise.)

Conifers are often valued as windbreaks and visual screens. In the garden, their myriad forms, distinctive textures, and all-season color make them important as structural elements and backdrops for other vegetation, design techniques that conifer devotees use with particular skill and creativity. Yet the ecological role of conifers, especially with regards to our native wildlife, remains largely unappreciated by many gardeners and landscape designers.

While most any conifer, regardless of nativity, offers some degree of nesting and cover for wildlife, conifers indigenous to North America afford all the components of habitat (i.e., forage, nesting, and cover). How native conifers host our wildlife is fascinating and can be readily observed on residential properties. These host relationships also hold significance for gardeners and conifer aficionados alike.

North America is home to conifers in fifteen genera (Abies, Chamaecyparis, Cupressus, Larix, Juniperus, Picea, Pinus, Pseudotsuga, Sequoia, Sequoiadendron, Taxodium, Taxus, Thuja, Torreya, and Tsuga). [1] Pines are among the most abundant, numbering over forty species. Seeds that mature within pinecones sustain turkeys, grouse, quail, dozens of song birds, chipmunks, mice, voles, and several types of squirrels, while pine needles constitute forage for over two hundred known species of moth and butterfly larvae, many of which rely solely on pines for food. Insects that feed on pine needles, in turn, become essential food sources for beloved nesting and migratory birds. In his recent book Bringing Nature Home, entomologist Doug Tallamy recounts how one spring he observed a pair of bluebirds rear their young almost entirely on sawfly larvae gathered from white pines in his backyard. [2] Indeed, ninety-six percent of our terrestrial birds feed their young in part or exclusively on insects, and the almost fifty percent decline in North American bird species within the last fifty years can be partially attributed to loss of native plants serving as food for native insects, which generally cannot process the leaf chemistry of alien plants. [3]

Some gardeners may not want to attract insects for fear of unsightly foliar damage. A diversity of native plants, however, supports a diversity of natural predators that keep insect populations in check. In fact, a recent study revealed that on suburban properties landscaped with native plants only three percent of the leaves were subject to insect damage. [4]

As residential and commercial development converts needleleaf forests to landscapes of turf and non-native ornamentals, bird species such as crossbills (a small bird in the finch family) find it difficult or impossible to meet their food and nesting needs. Crossbills use their uniquely evolved offset mandibles to access seeds inside spruce, pine, and fir cones. One study found that to survive a typical northern winter crossbills need to eat spruce kernels approximately every seven seconds during daylight hours. [5] Birds and small mammals that cannot actively shred cone scales retrieve seeds dropped by crossbills (as well as red squirrels). Owls and hawks in turn prey upon these ground-feeding animals.

North America’s four species of hemlocks provide forage for more than twenty known insect species. Birds that nest in hemlock’s dense foliage include the veery, the golden-crowned kinglet, the dark-eyed junco, the pine siskin, the sharp-shinned hawk, and numerous warblers (one of which is even known as the hemlock warbler). Similarly, the needles on North America’s nine fir and seven spruce species feed over 150 known species of moths and butterflies while songbirds and small mammals eat the seeds, and animals of all kinds nibble on needles and young twigs, particularly in winter when other food sources are scarce (one animal, the spruce grouse, actually changes the size of its intestinal tract in the winter in order to process the resins and terpenes in conifer foliage). Yellow-bellied sapsuckers make feeding wells in fir bark, and solitary vireos, yellow-rumped warblers, and evening grosbeaks can frequently be found nesting in firs within their native range. Meanwhile, prostrate conifers like Canada yew (Taxus canadensis) function primarily as cover and nest sites.

Conifers and animal species sometimes develop mutually beneficial relationships. A biologist studying eastern red cedars (Juniperus virginiana) determined that seeds passing through the digestive system of cedar waxwings (so-named for their preference for red cedar fruit) are three times more likely to germinate than seed that simply falls to the ground. [6]

Straight species as well as horticultural selections of native conifers can be purchased at garden centers, nurseries, and special occasion plant sales. While discussion of particular species and cultivars exceeds the scope of this article, some principles for using native conifers are listed below:

• Determine the extent to which you wish to emulate native ecosystems. A large site may allow for the design of a functioning ecosystem using solely native species while a smaller site might feature a perimeter of site-appropriate natives with more formal plants closer to the house. Natives and non-natives can be combined to create beautiful, ecologically rich gardens as long as non-native species that disrupt regional ecosystems are avoided. [7]
• Select conifers native to your ecoregion. They will be better adapted to your local conditions and will best match the needs of wildlife indigenous to your ecoregion.
• Use local genotypes if possible. A plant originating thousands of miles away from your home landscape may not be suited to the conditions of your garden and in some cases may adversely affect the genetic integrity of local native plant populations.
• Know a plant’s reproductive requirements. Some conifers are dioecious (male and female flowers on separate plants). Female Juniperus virginiana, for instance, produce fleshy blue, berry-like cones, and a good fruit crop depends upon male and female trees in proximity.

By utilizing traditional design principles, native conifers such as the Chamaecyparis thyoides ‘Andelyensis’ in this scene can be integrated into a variety of garden settings.

While more than one hundred cultivars of eastern arborvitae (Thuja occidentalis) are commonly available, many native conifers remain underrepresented in the trade: for instance, even though North America is home to seven spruce species, Colorado blue spruce (Picea pungens) is the only native spruce widely sold as an ornamental. This lack of diversity in the ornamental landscape ultimately impacts the health of our wildlife populations. “For the first time in its history,” writes Doug Tallamy, “gardening has taken on a role that transcends the needs of the gardener. Like it or not, gardeners have become important players in the management of our nation’s wildlife.” [8]

Numerous resources exist for those interested in using native conifers. Tallamy’s Bringing Nature Home lists conifer species (as well as other native plants) by major geographic region. Edward Cope’s Native and Cultivated Conifers of Northeastern North America (Cornell, 1993) and Michael Dirr’s classic Manual of Woody Landscape Plants (Stipes, 1998) describe hundreds of native conifers and their cultivars. Helpful online starting points include The Gymnosperm Database and sites like www.plantnative.org and www.for-wild.org. Naturalist groups, native plant societies, and local chapters of organizations like the Sierra Club also provide an excellent source of first-hand experience, in addition to the camaraderie of shared interests.

Conifer aficionados appreciate and use conifers with a special zest, creating unique collections that reflect their horticultural interests and personal tastes. This practice dates back over five hundred years when wealthy, botanically minded Europeans assembled living collections of exotic and curious plants that often included vegetation of North American origin (Thuja occidentalis, for instance, was grown in Paris as early as the sixteenth century [9]). Arguably these early collections had less need to fulfill ecological functions in a less fragmented environment subject to fewer human pressures. Today, with nowhere on the planet untouched by human influence, the stakes of this practice are quite different. With substantial modifications to our natural environment comes the burden of responsibility—as well as the potential for new meaning and fulfillment for those who put spade to earth. “Gardeners have the opportunity to make a difference,” writes Tallamy, “in this case the ‘difference’ will be to the future of biodiversity, to the native plants and animals of North America and the ecosystems that sustain them.”[10] Plant collections remain viable and satisfying pursuits capable of expressing personal creativity, but they can—and arguably must—now be enriched by new ecological knowledge (like that advanced by Tallamy) that can transform them into functioning, dynamic plant communities rather than biologically static assemblages of individual specimens.

Benefits of using native conifers of course extend beyond providing wildlife habitat. When properly sited, native conifers require limited inputs and are generally adapted to local weather patterns. (Hemlock’s slender outer branches, for instance, easily shed snow, thereby limiting winter breakage.) Use of native plants also expresses regional character in an era of landscape homogenization.

Using native plants cannot deliver us to a pure, mythical eco-utopia but it can help us to (re)develop landscapes that are not only biologically diverse and resilient but also beautiful. Such an approach benefits wildlife and ultimately the ecosystem services we all depend upon, but it also offers us something even more, something akin to mystery and a sense of connection in our own backyards. By consciously engaging with the dynamics of our regional ecologies, we do more than seek to sustain our world—we find ourselves cultivating the wondrous processes of life itself.

Larry Weaner has been a landscape consultant, author, lecturer, and educator for over thirty years. In 1982 he founded Larry Weaner Landscape Associates, a firm known for integrating the traditions of garden design with the science of ecological restoration. His design and restoration projects have received national awards and been featured in numerous publications. In 1990 Larry developed New Directions in the American Landscape, a national conference series dedicated to the study of natural landscape creation and restoration. He is a past Board Member and Environmental Committee Chair of the Association of Professional Landscape Designers.

Jenna Webster is a designer with Larry Weaner Landscape Associates. She received a master’s degree from the Conway School, a graduate program in sustainable landscape design and planning.

 

Native Perennials in the Garden

by Larry Weaner

(First appeared in NOFA Guide to Organic Land Care, 2009-2010. All photos by Larry Weaner unless indicated otherwise.)

Before we ask, “What perennials should we plant?” we may want to ask the larger question, “Why do we plant perennials?” In the past, herbaceous plants were used mainly to add color. In nature they serve many important functions, and garden designers can use them in many of the same ways. This approach can be particularly useful as we begin to look for alternatives to mowed lawn, and find ourselves planting far larger areas than have been traditionally allotted to the garden. Thinking of perennials as the “ground layer” of the landscape, as opposed to the “flower border” makes their functional role much easier to envision.

Fig. 1. Native perennial garden

What then are some of the functions of the perennial ground layer in nature, and how can these functions be incorporated into garden design?

A. Stabilization

This includes erosion control, and the prevention of invasion by other plants (in garden parlance, weeds). Many landscape gardens are planted with trees and shrubs, leaving extensive areas of exposed mulch. When perennials are added to the mix, they are often arranged in isolated groupings, mainly to add color. Leaving exposed areas of mulch creates an open invitation to weeds. Taking advantage of the stabilizing potential of a competitive, dense herbaceous layer can significantly reduce the weeding necessary to maintain the landscape as well as eliminate the need for costly annual mulching.

The herbaceous associations found in our native plant communities can serve as models for the successful design of these compositions. Observing these associations and adapting them to the garden can be extremely useful.

Some plants grow naturally as a dense monoculture, and consequently can be competitive in the landscape when planted alone. Examples of this are Woodland Sunflower (Helianthus decapetalus); Hay Scented Fern (Dennstaedtia punctilobula), and Canada Anemone (Anemone canadensis). Some of these species, like Canada Anemone, are too aggressive for smaller gardens, but as the size of a planting increases so must the competitive ability of the plants that are being asked to colonize it. It becomes crucial for the designer to analyze the scale in which they are working and select plants that are capable, but not over-capable of doing the job.

Fig. 2. – Dennstaedtia punctilobula dominating the ground layer of a birch-spruce woodland (photo by Thena Webster)

Other plants require associate species in order to form a cover dense enough to stabilize the soil and inhibit weed invasion. In nature these compositions often exhibit far denser spacing than are commonly found in gardens, yet they have a graceful and balanced appearance in addition to a strong competitive ability. This is due to the complementary growth habits, both above and below ground, that the association has developed over many years of co-existence. Our native meadow or prairie communities are an excellent example of this. Butterfly Weed (Asclepias tuberosa), Wild Cream Indigo (Baptisia leucophaea), and Little Bluestem (Schizachyrium scoparium) are a dry meadow association that can also form a very successful garden composition. Planting them in the dense and intermingled fashion found in the prairie only enhances their effectiveness, both functionally and visually.

Fig. 3 – Schizachyrium scoparium meadow detail with Solidago species

B. Management of Water Resources

In nature, the herbaceous ground layer reduces the evaporation of existing moisture in the soil through its vegetative cover. In addition, the foliage and roots of herbaceous perennials increase the infiltration of rainwater into the soil, thereby maximizing recharge of the underground aquifers. This also reduces runoff, decreasing erosion and flooding as less water travels through the watershed.

Wetlands have a particularly important role in this regard. Not only do they serve as massive water infiltrators, but also as pollution buffers as contaminants in the water are filtered out while passing through the leaves and roots of the herbaceous vegetation.

As water issues are now front and center in our list of ecological concerns, it has become increasingly important to understand the interactions of water and the herbaceous ground layer in nature.

Replacing runoff-prone lawn areas with meadows and other native herbaceous vegetation can increase infiltration and reduce runoff. Rain gardens, or depressions planted with native wetland perennials, are designed to collect water and maximize infiltration, reproducing in the small scale some of the benefits of naturally occurring wetlands.

Fig. 4 – Lowland meadow

Far from being an aesthetic liability, these plantings can contribute visual diversity to the landscape and afford the opportunity to incorporate some our most beautiful perennials, from the bold and architectural Angelica: Angelica purpurea to the diminutive but floriferous Meadow Beauty: Rhexia virginica.

C. Providing Habitat for Wildlife

Herbs in the landscape are very important to numerous forms of wildlife. Many bird and mammal species require cover at various times of the year. Birds eat the seeds of many herbaceous perennials, and some butterfly species utilize perennials as host for their larvae, including Milkweed species (Asclepias incarnata, Asclepias syriacus, Asclepias purpurescens, etc.), which are the sole host for Monarch Butterfly larvae.

In addition to these rather obvious benefits to wildlife, a myriad of lesser-known interactions also occur. The leaves of Cup Plant (Silphium perfoliatum) collect water after rains, which is consumed by small insects. Birds in turn feed on these insects as they drink, a chain of events made possible by this perennial plant.

Fig. 5. Rainwater collected in the leaves of Silphium perfoliatum.

Hedgerows are often left over from agricultural landscapes, and consist of trees, shrubs and tough herbaceous edge species like Goldenrods (Solidago species), Bee Balm (Monarda fistulosa), and Mountain mint (Pycnanthemum virginiaum). They serve as crucial wildlife corridors between isolated natural areas, substantially increasing their ecological value.

Owners of properties in residential developments can achieve similar results by planting consecutive native “hedgerow” gardens on their rear yard perimeters. Ground layer perennials are crucial as they provide a source of cover for the migrating fauna. This ground layer can also serve as a visual transition to more traditional plantings on the property by extending into the open yard, with a more gardenesque composition. An additional byproduct of this approach would be the visual integration of the individual properties in our neighborhoods, a characteristic that is sorely needed in many of our residential developments.

Fig. 6. – “Hedgerow” style garden

 

D. Fostering Natural Processes of Change

Herbaceous plants play an important role in the successional processes of change that occur in virtually all plant communities. In many areas of the US, the herbaceous meadow is a temporary vegetative state that occurs after disturbance, and yields over time to the establishment of woodlands. Even where prairies persist as a long-term plant community, a series of compositional changes occur, as annuals, biennials and short-lived perennials give way to the longer lived perennial plants of the mature prairie.

In traditional landscape design, the only form of change is the increase in size of individual plants, but compositional change can also be incorporated. As in the prairie, fast establishing short lived plants (eg: Dotted Mint: Monarda punctata, Black Eyed Susan: Rudbeckia hirta) can be seeded or planted, to form a temporary cover, while longer lived perennials (eg: Culvers Root: Veronicastrum virginicum, Blazing Star: Liatris species) are getting established.

Fig. 7 – Two year-old meadow with Rudbeckia hirta and other short-lived species.

Fig. 8- Late-stage meadow with Veronicastrum virginicum and other later stage meadow species.

In moist areas, wetland species can be combined to produce a similar relay process, with early colonizers like Cardinal flower: Lobelia cardinalis passing the baton to the late stage perennials like Pink Turtlehead: Chelone lyonni and Blue Flag Iris: Iris versicolor.

In other instances, a meadow composition can foster the development of a woodland landscape. Newly planted trees take years to form a canopy capable of supporting woodland understory plants. A dense seeded meadow planting can be a cost-effective and aesthetically satisfying way to stabilize the site in the interim. As shaded conditions occur, the meadow can be replaced with ferns and woodland wildflowers.

Fig. 9 – Meadow as a placeholder until the woodland becomes established.

As all of the above examples illustrate, a great deal can be accomplished by planting perennials, less as individuals, than as interrelated parts of a plant community, occupying identifiable niches in both space and time. These communities can be literal or adapted translations according to the type of garden, but in either case, the plants have a functional job beyond looking pretty.

If this all sounds like restoration ecology as much as garden design, that is precisely the point. Blending the sophisticated artistic techniques of the garden designer with the dynamic patterns revealed by the ecological sciences can only serve to enhance the manageability, ecology, and ultimately, the beauty of our landscapes. The perennial ground layer is as much the foundation of the house as the icing on the cake.

Wildflower Meadows: Let’s Get Real

By Larry Weaner

Americans use enormous quantities of water, fuel, fertilizers, and pesticides to make lawn grow vigorously, only to then spend time and money weekly to keep it short. So why, even amidst growing ecological awareness, do lawns continue to dominate our landscapes? Some reasons for lawns make sense, but lack of practical alternatives may be a major cause. If we’re ever to be weaned from over-reliance on lawns, dependable, cost effective solutions must be available.

Why have wildflower meadows not become a staple of the American landscape? Designed meadows have been available for years and have received great amounts of publicity. Claims that they can provide a carpet of beautiful flowers, with little or no maintenance would seem to make them an ideal solution. They have not proliferated because all too often they have failed. Deficient seed mixes and poor planning have caused too many of these projects to be one year success stories which end with a massive weed invasion and a showing of the familiar horror flick, “Return of the Giant Mower”. In some cases they have failed because the expectations generated have been so unrealistic that even a success can seem to be a failure. All of this has done more harm than good, as much of the inclination and energy for change on the part of the public has been squandered.

Photo by Ian Caton

In fact, wildflower meadows, if planned, installed and managed properly, can contribute tremendously to naturalizing the American Landscape. When integrated into a well-designed landscape matrix, a meadow can help transform a residential property into a beautiful and stimulating home environment while vastly reducing quality time with a noisy mower. Large corporations can dramatically reduce maintenance costs, as has been documented on numerous projects, and public highways and parks can enhance our spectacular and diverse native landscape on a visual and ecological level.

Before we begin to discuss how to obtain these results, we need to clarify what we mean by a native wildflower meadow and how it differs from the one-year wonders we have previously described. In order to fulfill the requirements of long term sustainability and low maintenance, the meadow must be designed as a functional plant community first and a flower garden second. Only by understanding and incorporating the compositions, patterns and processes inherent in our naturally occurring meadows and prairies can we create landscapes that will be viable over long periods of time without massive amounts of assistance.

Does this mean that we must sacrifice aesthetics for sustainability?

Not at all. True, we won’t see a wall-to-wall carpet of colors as is commonly depicted on wildflower seed packets, but we need not lower expectations, only change them. A visual foundation of native ornamental grasses glimmering in the sun and swaying in the breeze, complemented by graceful drifts of wildflowers will provide a truly spectacular scene, more inspiring and certainly more sustainable than the riot of color depicted on the seed packet. Instead of waiting in dread to see what will emerge the second year after the annual flowers have expired, we can enjoy an ever evolving natural landscape that changes from season to season, and year to year as it reflects the beauty and grace of our native meadows and prairies.

Photo: Ian Caton

Sounds very nice, right, but how do we get it done? While we are waxing poetic the weeds have something else in mind. The following are some of the most important elements for designing, implementing and managing a native meadow that we can feel confident will fulfill our expectations.

SITE ANALYSIS

Analysis of the site will be the first order of business and there are four main aspects to be considered.

Item number one is light exposure. Full sun is a necessary requirement for a meadow planting. Insufficient sunlight will favor woody species over herbaceous wildflowers and grasses causing an increase in maintenance requirements.

Soil type will be your next consideration. It is imperative to understand and identify which soil you are working with (sand, loam, clay, etc.) in order to select plants that will adapt successfully to the site. If poor soils exist, a decision can be made to either amend the soil or narrow the plant list to those that will tolerate that specific condition. In some cases bad soil conditions, either poorly drained or very dry, can provide a competitive advantage to the meadow species. Many of the most notorious weeds favor richer soils while there are numerous native flowers and grasses that thrive in poor conditions. Plants with strong ornamental characteristics such as Butterfly Weed (Asclepias tuberosa) and Little Bluestem (Schizachyrium scoparium) will grow well in dry sands while Pink Turtlehead (Chelone lyonii) and New England Aster (Symphyotrichum novae-angliae) will thrive and flower in poorly drained clay soils.

Asclepias tuberosa and Pycnanthemum tenuifolium

High soil nutrient levels will be less important than in traditional landscapes as most native plants are generally adapted to existing conditions. Barring an extreme deficiency, fertilization should be avoided as it will probably favor the weeds more than the desirable species.

Grade and topography can effect a number of decisions to be made in planning the meadow. A north slope may not be favorable to meadow plants as they will receive less direct sunlight. If the meadow is in a low lying area and remains wet during spring thaw and rains, plants adaptable to these conditions should be selected. A sloped site may favor spring as opposed to late fall seeding to avoid washing of un-germinated, dormant seed during winter. Also micro variations within the site can be noted and considered in the plant selection and placement process in order to further match the plant to its proper environment.

Analyzing existing growth on and adjacent to the site can yield extremely valuable information relating to what plants will grow well on the site and what specific weedy species are likely to be a problem. If a problematic weed is existing on or near the site it is highly recommended to eradicate it beforehand in order to avoid future infestations.

SEED MIX COMPOSITION

Based on your analysis of the site, you can now select the plant species that will comprise your seed mix. The plants that will afford the best long term results will invariably be those that are found in conditions similar to your site and are native to your particular region. Although the temptation is great to include showy exotic species selected for their floral characteristics, their likelihood of survival is far lower. While plants which are marginally adapted to a site can often survive in a cultivated garden where competitors are eliminated through weeding, mulches and fabrics, in a highly competitive meadow planting only the most adapted vigorous plants will survive.

As in most naturally occurring meadows and prairies, grasses should be a major component of the plant mix. They are the single most important component in stabilizing the meadow from both a functional and visual point of view. Only clump forming grasses should be used including Little Bluestem (Schizachyrium scoparium), Indian Grass (Sorghastrum nutans), and Purple Lovegrass (Eragrostis spectabilis). A nurse crop usually composed of a fast germinating, clump forming grasses such as Canada Rye or Common Oats should also be included to help secure the site from weed invasion and erosion during the first season. This is very important. The initial phase is the most volatile as the longer lived perennials and grasses are not yet well enough established to control the site.

An important concept to understand when combining plant species is the concept of niche. A study of a mature Midwestern prairie will reveal an incredibly dense tapestry where every possible space is occupied. A tiny section of five foot prairie will contain a canopy, numerous mid layers and a creeping understory. Mat forming root systems occupy the upper soil layers while deep fibrous and tap roots hold down the fort below. If all of these elements are present the meadow will have a strong capability to resist weeds. There is no place left for them to grow.

In addition to filling the various niches in space, you need to fill the niches in time. (Don’t worry, I’m not getting weird on you. I have something concrete in mind). First is seasonal time. Some plants are active in warm weather while some plants are most vigorous during the cool seasons, particularly spring. By including both types there will be no seasonal opening for weed invasion. A second type of niche relating to time is measured in years. Some plants establish a cover during the first year, some during the first few years and some long lived plants may not have a serious presence for many years. All of these need to be present to avoid a weak stage in the meadow’s competitive ability.

Variation in cool season and warm season growth across the growing season

Unfortunately the vast majority of seed mixes on the market have given little or no thought to any of these functional considerations. They are mostly composed of annuals, biennials and short lived perennials that are selected for quick results at a cheap price. It is very unlikely that they will last more than a year or two. If you put Flax, Poppies and Cosmos in the ring with Canada Thistle, Japanese Honeysuckle and Oriental Bittersweet it’s not hard to guess who will be left standing after the last round. You need a far meaner crew than that to stand up to those neighborhood bullies. Even the all perennial mixes sometimes offered do not usually include sufficient long term species to make the planting competitive beyond the early stages. In other words there are perennials and there are perennials.

Why is it so difficult to find a seed mix that provides the plants needed for the long haul? The answer can be found in an examination of the different reproductive characteristics of long and short lived herbaceous plants. Annuals, biennials and short lived perennials produce large amounts of flowers and seed early in life as a proliferation strategy, compensating for the fact that they won’t be alive very long. This makes their seed cheap to produce and their floral impact immediate. Long lived perennials on the other hand, planning to stick around through good times and bad, are more interested in expending their energy on early vegetative growth to gain a foothold amongst the competition. Flower and seed production is a low priority at this early stage. The bad news here is that a seed mix designed for the long term makes two years to produce flowers and will inevitably cost more. The good news is that you won’t get stomach cramps every time you receive a phone message from your two and three year old meadow clients.

Established meadow with dense, diverse growth

There is still one more item on the seed mix wish list. Even if the seed composition contains sufficient long term, competitive plants to produce a sustainable meadow, these mixes need to be available not only according geographical region (northeast, Midwest, etc.), but by soil preference. It makes no sense to spend time determining that you have a poorly drained site containing a heavy clay soil and utilize a mix in which half of the plants are native to dry sandy conditions. Meadow mixes formulated for dry, mesic, and wet soil conditions, composed of plants native to the particular region will undoubtedly serve as the best possible foundation for a successful and efficient mix.

The best route to take however is to order seed by individual species. You can further fine tune the site adaptability of your plant composition and segregate species according to micro areas within the site. There are a growing number of suppliers that offer native perennials and grasses in this form and expert advice is often an additional bonus. Individual species selection can also allow for additional design flexibility regarding the aesthetic aspects of the meadow. Consideration can include combinations of flower color and forms, foliage textures and succession of bloom as in any well planned landscape garden.

In addition, plants to encourage wildlife can be included, adding another dimension to the enjoyment of the landscape. The seed heads of many of the grasses and wildflowers will attract birds to the meadow (Liatris, Rudbeckia), particularly in winter, while a number of meadow plants are particularly attractive to Hummingbirds (Lobelia, Monarda, Penstemon).

Monarda seed heads in a Schizachyrium scoparium meadow

In regards to installation of the meadow, much of the process is similar to turf grass seeding. Creating a finely graded seed bed, incorporating the seed into the soil, tamping or rolling for good seed to soil contact and mulching with salt marsh hay or a clean straw is necessary. Timing can be slightly different. Sowing in the fall is limited to late dormant seeding and the spring seeding period can extend into early summer. Late fall sowing is not recommended on sloped sites where erosion can be a problem.

Site preparation will be of the utmost importance in achieving a successful meadow. It begins with the elimination of existing growth. The most common methods are several repeated applications of short lived herbicide, repeated tilling or a combination of the two. Tilling will bring to the surface dormant weed seeds which must be allowed to germinate and then shallowly cultivated or sprayed with herbicide before planting. This can be avoided with a no-till seeding if a shallow seed bed can be worked up among the dead plant material.

A site prepared for seeding.

DISTRIBUTING THE SEED

Due to the small seeding rates of the perennial flowers and some of the grasses it will be necessary to mix the seed with an inert material (sawdust, sand etc.) before spreading. Arrangement of plants in the meadow is best done by combining the designer’s creativity with the patterns that occur in nature. Naturally occurring meadows rarely have a homogeneous mix of species evenly scattered throughout the area. More commonly, an individual plant or plant group, usually including grasses, will dominate, with smaller colonies of plants occurring in pockets or drifts. Replicating this arrangement can yield a natural and appealing meadow which relies more on the form and textures of grasses interplaying with subtle touches of color, than a difficult to obtain constant explosion of bloom.

Seed mixed with a carrier and ready for hand spreading

Sometimes small pockets of an isolated species can correspond to a micro condition on the site such as a low moist area. By following the lay of the land in placement of plants or plant groups, you not only increase survivability of those plants, but create a landscape that automatically appears natural and graceful.

Seeding specialty overlay mixes by hand

Meandering paths and secluded sitting areas can be seeded with low grasses and spring ephemeral flowers (Bluets: Houstonia caerulea, Violets: Viola species) to be occasionally mowed during the season for easy access. This can allow the sights, smells and sounds of the landscape to be appreciated from within, adding an experiential element to the planting. The lines where meadow meets mowed lawn can become an additional feature of the landscape creating a graceful transition from the controlled to the wild landscape.

POST PLANTING MANAGEMENT

An understanding of ‘ecological succession’ will be extremely important for the maintenance of the meadow. This is the process by which a disturbed area progresses naturally from herbaceous meadow (first annuals then perennials) to woody shrubs and pioneer trees and finally to a mature forest. In dry portions of the country various forms of prairie are the mature stage of the process. In establishing a permanent meadow where woods naturally predominate we are arresting the process of ecological development at the herbaceous perennial stage. By understanding nature’s next ‘move’ throughout the process we are better able to make intelligent decisions resulting in less maintenance requirements and a more successful end result.

Stages of succession from meadow to shrub-thicket to forest

Also the client must understand that although their meadow, once established, will require substantially less maintenance than mowed lawn once established, the first one to two years will require guidance in order to achieve successful results. A maintenance plan should be in place before starting, to insure that this crucial portion of the project is not later neglected.

After planting, it will be necessary to carry out a weed control program to insure the successful establishment of the meadow. The methods that will be most appropriate will be determined by the size of the project, maintenance budget, method of installation and what weed species appear. As the process of ecological succession would suggest, the first year will bring a rapid cover of annual weeds while the perennial wildflowers and grasses are slowly developing underneath.. This is to be expected, and if managed properly, is not a problem.

By mowing the meadow every 6 weeks to a height of 4-6″, you will not only prevent the annual weeds from seeding, but insure that the young perennial plants growing below your mow height receive enough light for strong establishment. These perennials will emerge the following year far stronger than if they had been buried under 4 feet of annual foliage the first year. This is why the inclusion of annual wildflowers in your seed mix can be detrimental to the long term health of the planting. Annual wildflowers are included for their ability to bloom the first year. In order for this to occur you will be prohibited from mowing, this will allow annual weeds to go unchecked and deprive the emerging perennials of the light needed for optimal growth.

First year meadow growth (annual cover crop and meadow seedlings)

During the second year the faster growing perennials (such as Black Eyed Susan: Rudbeckia hirta, Purple Coneflower: Echinacea purpurea, and Bee Balm: Monarda fistulosa) will begin to provide color and the entire planting should be well enough established to allow a decrease in weed control.  You will need to monitor the planting for those weeds that can cause problems for the meadow.  If needed, control can be obtained through spot herbicide application, manual weeding, or an additional mowing/cutting during the most active growth period of the problem weed.

Meadow in third-to-fourth year

By the third year the native meadow plants should be fairly dominant on the site and able to resist weed invasion with minimal management. Maintenance will consist of periodic monitoring and one mowing or burn either in the late winter or early spring.

Annual late winter/early spring mowing

Once established, the native meadow planting exemplifies the blending of horticulture, design, and ecology and results in an easily managed, ecologically sound and visually dynamic landscape to be enjoyed for years to come.

The current trend toward ecological concern, economy, and appreciation of the natural world has created a public eager for new ways to incorporate nature into their homes, businesses and public lands. Native meadow and prairie plantings blend perfectly with these emerging attitudes, presenting an outstanding opportunity for those landscape designers, architects and planners who have made an effort to understand the ecological principles needed for their successful design and implementation.

 

Recommended Perennial Wildflowers for Northeastern Meadows

(D=dry, M=mesic, W=wet)

Asclepias tuberosa: Butterfly Weed | D, M
Symphyotrichum novae-angliae: New England Aster | M, W
Baptisia species: False Indigo | M, D
Boltonia asteroides: Thousand Flowered Aster | D, M
Chelone glabra: Pink Turtlehead | M, W
Chrysanthemum leucanthemum: Oxe Eye Daisy | D, M
Coreopsis lanceolata: Lance Leaf Coreopsis | D, M
Echinacea purpurea: Purple Coneflower | D, M
Eupatorium fistulosum: Joe Pye Weed | M, W
Filipendula rubra: Queen of the Prairie | M, W
Iris versicolor: Blue Flag Iris | W
Liatris species: Blazingstar | D, M, W
Lobelia cardinalis: Cardinal Flower | M, W
Lobelia siphilitca: Blue Lobelia | M, W
Mimulus ringens: Monkey Flower | W
Monarda fistulosa: Bergamot | D, M
Penstemon species: Beardtongue | D, M
Ratibida pinnata: Yellow Coneflower | D, M, W
Rudbeckia hirta: Black Eye Susan (self seeding biennial) | D, M
Solidago species: Goldenrod | D, M, W (Do not use Solidago canadensis, which, while it is native, is highly vigorous and tends to overwhelm desired vegetation.)
Tradescantia ohiensis: Spiderwort | D, M
Vernonia novaboracensis: Ironweed | M, W

 

Recommended Grasses for Northeastern Meadows

Andropogon gerardii: Big Bluestem | D, M
Bouteloua curtipendula: Sideoats Grama | D, M
Panicum virgatum: Switch Grass | M, W (live plants only as tends to form monocultures when planted from seed)
Schizacharium scoparium: Little Bluestem | D, M
Sorghastrum nutans: Indian Grass | D, M (live plants only as tends to form monocultures when planted from seed)
Elymus canadensis: Canada Wild Rye | D, M, W

 

Common Problem Weeds in Northeastern Meadows

Artemisia vulgaris: Mugwort
Cirsium arvense: Canada Thistle
Celastrus orbiculatus: Oriental Bittersweet
Lonicera japonica: Japanese Honeysuckle
Lythrum salicaria: Loosestrife (wet meadows)
Rosa multiflora: Multiflora Rose

Originally published in Landscape Design, Jan. 1996. Photos by Larry Weaner unless indicated otherwise.

Ten Elements of Natural Design

By Larry Weaner

(Originally published in American Nurseryman, Jan. 1996. Photos by Larry Weaner unless indicated otherwise. Republished in Connecticut Horticultural Society Newsletter, February 2010.)

The elements that make a landscape design “natural” are difficult to define. A landscape with curved bed lines, informal plant arrangements and no pyramidal yews does not always qualify as a natural landscape. And advocates of natural design are not necessarily eager to banish a host of beautiful exotics from the plant palettes of American landscape designers, replacing the plants with a motley crew of straggly natives.

The basic concept behind natural design, however, is fairly simple—to incorporate native plant communities into the designed landscape. But their successful incorporation requires a basic understanding of how native plants operate in nature.

Too often, random informality passes for “natural,” when in reality nature is highly ordered and anything but random. Understanding this order and using it in our designs is the key to making natural design workable and successful. This does not mean, however, that we must design exclusively with native plants, attempt to copy nature exactly, or exclude the influences of other design styles. The goal is to create a framework for the overall designed landscape that has an aesthetic and ecological relationship to our indigenous landscape through the use of native plants in their natural associations.

The basic considerations of natural design can be broken down into three categories: aesthetic, managerial and environmental.

The aesthetic aspect of our designs is highly subjective, and individual style varies greatly. Some designers may object to uniformly patterning their work on the native landscape, feeling they are homogenizing their designs or stifling their artistic expression. But, as landscape designers, our medium is the land.

Unlike a painter whose art occupies an isolated canvas, our work visually interacts with the surrounding landscape, both natural and constructed. We therefore have a responsibility to contribute continuity and a sense of place to the larger landscape. To successfully accomplish a marriage of art and nature, we should sometimes put our egos aside and let nature be our guide.

The managerial aspect of natural design is tied to the fact that reducing landscape maintenance is a strong priority for virtually all our clients. Natural design techniques can make a great contribution in this regard. This does not mean that natural landscapes are maintenance-free and can be completely left to natural processes with no human guidance, however.

Photo © Rob Cardillo

What natural design does mean is that landscapes that incorporate native plants and natural processes will require less time, money and energy for upkeep than designs in which plants are selected and combined for ornamental effect alone. A purely ornamental garden is like a beautiful, sleek automobile with no engine. It may be nice to look at, but the only direction it will go without help is downhill. We will be perpetually required to tow these gardens up the hill with fertilizers, watering hoses and weeding forks.

The environmental considerations of natural design are equally important. Many detrimental landscape practices can be minimized or eliminated. Such landscape practices include the excessive use of pesticides, herbicides, inorganic fertilizers, fossil fuels burned while mowing large areas of turf grass, and exotic species that have aggressively naturalized in the wild.

Natural design aims not only to reduce these negative effects, but to make a positive contribution to the surrounding environment as well. Naturally designed landscapes can also become functioning ecosystems capable of providing food and shelter for animals and insects, while helping to perpetuate many native plants whose habitats are being reduced through development.

Now that I’ve covered these main categories, I’d like to discuss 10 elements of natural design and examples of how to apply them to our work.

1. Cultivate in your clients an appreciation of the beauty in nature.

Everyone admires the beauty in a majestic mountain range or a towering waterfall, but most of what we can create in our landscapes is more subtle. The contrasting patterns of straight and leaning tree trunks in a woodland grove, a single turk’s cap lily (Lilium superbum) nodding above a bed of meadow grass, or the layered branches of a pagoda dogwood (Cornus alternifolia) in a woodland edge may be an acquired taste.

A native old field in winter is a prime example of how learning to see the landscape anew can open a whole new vista of aesthetic possibilities. The glistening orange of little bluestem (Schizachyrium scoparium) in the sun, punctuated with columnar green patches of eastern red cedar (Juniperus virginiana) is a spectacular American scene, and a much more warming sight on a frigid February morning than a curled up ‘PJM’ rhododendron (Rhododendron ‘PJM’) in a crispy bed of pachysandra (Pachysandra terminalis). Designers who cultivate in their clients an appreciation of the natural world around them will find their work to be more easily accepted.

2. Minimize disturbance of existing native growth.

Protecting existing native growth, particularly woodlands, is easier and less expensive than trying to restore it after it’s destroyed. Even our best restoration efforts may never achieve the beauty and mystery of an undisturbed woodland. Developers, architects and clients need to be aware of the benefits of considering ecological systems before designing the structures for the site. Early decisions relating to the siting of buildings, topographic changes and excavation disturbance can help minimize destruction of natural growth during construction. Unfortunately, landscape designers and architects often are brought in after construction is complete and have no opportunity to influence the treatment of the existing landscape.

3. Decide how closely your design will emulate the native landscape.

The design will be determined by numerous factors including the character of the surrounding landscape, client dictates, architectural style, site characteristics and the scale of the site. A large site may allow for the design of a functioning ecosystem using strictly native species. A smaller residential site can be designed with a perimeter of site-appropriate natives, becoming more cultivated as the landscape nears the house. Native plant cultivars such as ‘Golden fleece’ goldenrod (Solidago sphacelata ‘Golden fleece’), ‘Purple Dome’ aster (Aster novae-anglia ‘Purple Dome’) and native azalea cultivars can be very useful in making a transition from wild areas to more formal ones.

4. Allocate the location of woodlands, open spaces and transitional areas.

Natural landcape patterns found in many areas throughout the country are formed by the interplay of woodlands, open landscapes and the transitional areas where they meet (edges or ecotones). A graceful and functional mix of these features will define the design before any plants are selected. Even small properties can be approached in this manner, often resulting in the illusion of more space.

5. Base your design on native plant communities found in similar conditions in the surrounding areas.

Determine which plant communities would have existed on the site had it not been disturbed, and use these as a design model.

Determining native plants is easiest on a site that still contains remnants of indigenous growth. If this is not the case, you can obtain information by observing nearby natural areas with similar ecological conditions, analyzing the soil and hydrology of the site, obtaining geological maps and studying the natural history of the area. If the post-disturbance soil and water conditions are no longer capable of supporting these plant communities, consider basing your design on a community with similar conditions.

6. Use and plan for natural processes of change to modify the landscape.

The indigenous landscape is a constantly changing system composed of plants, animals, insects, microorganisms and soils. Plants are not isolated entities, but participants in a system constantly in flux. Different types of systems change at different rates. The annual meadow immediately resulting from a disturbance may last for only one year, while the perennial meadow may last for 10 before yielding to pioneer forest species. By contrast, an old oak and hickory forest may last for hundreds of years if left undisturbed.

Photo © Rob Cardillo

Once these changing systems are understood, the designer can decide which aspects to encourage, discourage or manipulate to fit the requirements of the client and site. Designed landscapes need not be static photographs frozen in time forever, doing battle with the forces of nature.

7. Occupy all the spaces.

A basic law of almost any native ecosystem is that if nothing is currently growing in a given space, something soon will. The more available space is filled, the less opportunity there is for a weed to enter. Plants grow against each other, above each other and below each other. Even a 3-foot-tall meadow has a multi-layered structure designed to seal off the area.

This is also evident below ground, where fibrous rooted plants occupy the soil surface and coexist with deep taprooted plants “holding down the fort” down below. There are obvious lessons here for the designer interested in creating landscapes that have the ability to fight off weed invasion without the aid of mulches, fabrics and grub hoes. Mulched beds around isolated groupings of shrubs are an open invitation to neighborhood bullies such as Canadian thistle (Cirsium arvense), knotweed (Polygonum) and nut grass (Cyperus esculentus).

A mixed, densely planted herbaceous ground cover layer, composed of plants with complementary aboveground and belowground growth habits, will be far more successful at inhibiting weed invasion than any mulch. If this ground layer is also designed for succession of bloom and contrasting foliage texture, we can create a reduced-maintenance landscape that suggests the diverse tapestry of our native ground covers while achieving an artistic and colorful composition.

8. Increase ground water recharge by preserving rainwater on-site.

Current landscape practice often considers surface water as something to be eliminated. Meanwhile, water shortages are a frequent problem in our communities. Whenever we grade a property to direct surface runoff into the storm water system, we are sending a valuable commodity out to sea. Aquifer recharge, the replenishment of our underground water tables, depends upon the absorption of rainwater into the ground. We can assist this process by using ponds, irrigation catchments, porous paving surfaces and bog gardens.

Low wet areas can be converted into colorful assets by designing them as wet basins containing a range of colorful water tolerant plants like turtlehead (Chelone lyonii), Joe-Pye weed (Eupatorium purpureum), New England aster (Aster novaeanglia) and blue flag iris (Iris versicolor).

9. Employ alternatives to high-maintenance lawns.

The American lawn has become the focus of a great deal of controversy. Great quantities of water, fertilizers and fossil fuels are expended for lawn upkeep and the amount of pollution from herbicides, pesticides and small engine exhaust is well documented.

Although there is nothing inherently evil in a blade of Kentucky blue grass or the person who likes it, replacing substantial portions of mowed lawn with other, more ecologically friendly plantings would have a positive effect on our environment. A mowed lawn does serve a unique function in that you can walk, lay and play catch on it—activities that are difficult in a tall grass meadow or a cottage garden. It is possible, however, to offer alternatives that are affordable, easily sustainable, ecologically sound and aesthetically pleasing.

The first alternative to lawn is lawn. Not the resource-intensive grass monoculture that we normally plant, but a diverse ground cover of creeping broadleaf plants combined with slow-growing drought and disease-resistant grass cultivars or native grass species. These plants could include buffalo grass (Buchloe dactyloides), Pennsylvania sedge (Carex pensylvanica), wild strawberry (Fragaria spp.) and violets (Viola spp.). A lawn of this type would require little or no fertilizer or chemical application, and would need to be mowed less frequently than a traditional lawn.

Wildlfower meadows are currently the most popular lawn alternative as they can provide visually stimulating, low-maintenance landscapes. However, in order for these plantings to succeed in the long run, the majority of wildflower seed producers must completely revamp their mixes. Annuals and short-lived perennials selected for immediate floral effect must give way to long-term native perennials and grasses selected for function and site-adaptability, as well as aesthetics. By patterning these landscapes after our native prairies and grasslands, their exciting potential can be fully realized.

The most neglected lawn alternative is woodland. While open space is highly valued, it can be even more appreciated when contrasted with a shady tree grove. While this type of landscape would obviously take far longer to mature, a transitional period can be filled with a meadow or grassland landscape supplemented with trees. Woodland understory and ground layer plants can be added after a sufficient canopy is developed.

10. Exclude invasive, exotic plants in the native landscape.

A number of exotic species have naturalized so aggressively into our woods, meadows and wetlands that the natural plant diversity of these areas is destroyed. These include many commonly used ornamental plants such as Norway maple (Acer platanoides), burning bush euonymus (Euonymus atlatus), privet (Ligustrum), Japanese barberry (Berberis thunbergii). Russian olive (Elaeagnus angustifolia) and tatarian honeysuckle (Lonicera tatarica). Purple loosestrife (Lythrum salicaria), a European perennial that has attained enormous popularity, has completely destroyed the biodiversity of thousands of acres of wetlands. (Claims that its cultivars are sterile and therefore harmless have been proved false, as these cultivars eventually hybridize into fertile forms.) We should completely abandon using any plants that have proved to be invasive in the native landscape.

In addition, we should be looking into ways to identify and discontinue using any new plants that show likely potential for invading our natural areas.

Although natural design is not new, current public interest in natural aesthetics, reduced landscape management and environmental issues is making its widespread acceptance a real possibility. In order to capitalize on this opportunity, we need to develop concrete and reliable strategies for the design, implementation and management of these landscapes based on real ecological principles.

Landscape designers and architects influence the treatment of vast areas of land. We have a responsibility to treat the land as more than our personal paint canvas. The landscape designer should be part artist and part repairman, restoring some of the aesthetic qualities and environmental functions of the native landscape that have been destroyed. By making an effort to truly understand the workings of our indigenous landscape, and combining that understanding with the horticultural and design knowledge long associated with our profession, we can legitimately lay claim to the word “natural” when describing our work.

Photo © Rob Cardillo

Woodlands, Meadows and Transition Zones

Natural design can incorporate native woodlands and meadows, as well as transition zones between the two. In a limited space, you can adapt these elements to a smaller scale. Woodlands are the dominant plant community type in many areas throughout the United States. If left undisturbed, these open sites would revert to some type of forest community after passing through various stages of herbaceous and woody shrub composition. Therefore, where woodlands predominate, landscapes patterned after our indigenous forest should be a strong—if not dominant—component of our work. The re-establishment of woodland landscapes on open sites, both large and small, should also be considered as a primary option.

A natural woodland is composed of a multilayered tapestry of canopy and understory trees with a ground layer of shrubs and herbaceous plants. Trees of the same species are found at many different ages and irregular clusters, and do not necessarily have straight trunks and uniform heads. In fact, leaning and jagged trunks can often be the most interesting feature in the landscape.

Unfortunately, there is not enough space to create true self-sustaining woodlands on most residential properties. However, if the planting of site-appropriate native woodland species on the perimeters of suburban properties became commonplace, a series of continuous woodland corridors would be created, connecting existing isolated fragments of native forest badly in need of ecological interaction. The positive ecological impact of this would be quite significant, while the aesthetic advantages of suburban landscape in visual harmony with our native American forest would be easily apparent. Additional privacy would be a bonus.

Native meadows and grasslands are often the product of the disturbance of existing woodlands. This disturbance can result from either people (fire, bulldozers, chain saws) or nature (fire, storm, pathogens). If left alone, a succession of plant communities occupies the site. The process begins with herbaceous annuals and biennials, then leads to herbaceous perennials and grasses.

A mixed old field composed of herbaceous perennials, shrubs and fast growing pioneer trees follows. Finally, the site reverts to woodlands until another disturbance comes along, starting the process all over again. To preserve the open landscape then—be it lawn, meadow or perennial border—we must continuously arrest the successional process by artificially disturbing the landscape in various ways, such as by mowing lawns and weeding perennial gardens.

Although there are many different types of native meadows, they generally have one thing in common. The plant group most vital for their stability are the warm-season grasses such as Little Bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans) and Panic grass (Panicum virgatum). Although wildflowers receive the bulk of attention and are certainly an important aesthetically pleasing portion of the mix, it is the grasses that provide the stability for successful long-term results. Only through a combination of warm-season grasses and tough native perennials selected for site adaptability can we create dynamic and colorful landscapes that can live up to the low-maintenance expectations surrounding the wildflower meadow.

Woodland edges (or ecotones, in the language of the ecologist) are the transitional areas between the woods and the open landscape. They are, by nature, rapidly changing plant communities composed largely of herbaceous perennials, woody shrubs and vines. These communities can include species from both the woodlands and open landscapes that the ecotones separate. Additional species not found in either of the bordering landscapes may also be present. Some of the plants found growing in edges are the same pioneer species found in landscapes in transition from open to woodland communities.

We can design and manage a small woodland as an edge ecosystem, or selectively remove some of the edge species and manage the landscape to contain some of the aesthetic and functional characteristics of an interior forest. Ecotones are dynamic and diverse communities that hold a very prominent visual position in the landscape, and the design opportunities are exciting. Woodland edges also present both challenges and opportunities for the designer. Many of the most pernicious weedy vines such as Oriental bittersweet (Celastrus orbiculatus) and Japanese honeysuckle (Lonicera japonica) can be found in this type of environment where a combination of trees for support and adequate light for growth are present. A dense planting of desirable edge species, such as Arrowwood (Viburnum dentatum), Pagoda dogwood (Cornus alternifolioa) and Sweet fern (Comptonia peregrina) can help to eliminate these vines, but selective removal may be needed as a supplemental management tool in many cases.

Natural recruitment of Maiainthemum canadense, Dennstaedtia punctilobula, and Carex pensylvanica in a woodland setting. Invasive species have been selectively controlled (through cutting or herbicide treatment) to give the desired species a competitive edge and eventual domination of available resources. The shrub and vine layers can be added with protection from deer browse as necessary.