Wednesday, February 24, 2010

Creating Native Plant Communities

Many contemporary gardens are artful compositions designed to show off beautiful plants and elicit an emotional response. A main goal is that these compositions be ‘readable.’ This often requires that the ground plane be a smooth, weed-free layer of mulch. The ecological function of the plants and their interrelationships are not of primary concern. A more naturalistic approach to landscape or garden design puts a greater emphasis on the ecological function of the garden; this includes a well functioning plant community.

In a plant community there are plants to fill all available spaces, to the extent that the soil and moisture conditions allow. The spaces are filled on both a spatial and a temporal basis. There are different plants growing and receding over the course of a year. For example, one spot may be occupied by a wild geranium in the spring, followed by a big-leaf aster later in the summer and into fall, and all this could be happening beneath a shrub or small tree. The benefits of the diverse community of plants is that the ground is always covered, which blocks out weeds without the addition of a layer of mulch. These plant layers also provide cover for many beneficial insects – reducing the need for pesticides.
Another huge advantage of working with plant communities is that all these plants grow under very similar conditions. So soil conditions, water needs, climate and light requirements are all consistent and you don’t need to fuss over any individuals in the garden.

Designing a Plant Community

In nature, plant communities eventually develop on their own. In the residential garden we can play a role in what that community looks like. The first step is to determine the type of habitat you will be working with. Edith Roberts and Elsa Rehmann in American Plants for American Gardens, first published in 1929, taught about designs that were sensitive to the site and how to use appropriate natural plant communities in those landscapes. They describe habitats and provide lists of plants appropriate to rural Connecticut.

Another book with more emphasis on the design process is Natural Landscaping – Designing with Plant Communities, by John Diekelmann and Robert Schuster. These authors draw their examples from native plant communities found in the northeastern quadrant of the US. They describe the main plant regions and how the plant communities function in them. In the back of the book are lists of native plants found in 13 types of communities ranging from boreal forests in the north to savannahs and dry prairies.

For even more detailed descriptions of natural habitats I would look to resources like Wetland, Woodland, Wildland. A Guide to the Natural Communities of Vermont, by Elizabeth Thompson and Eric Sorenson. This book describes the features and major plant species encountered in over 80 natural communities found in Vermont. Similar information can be found for states or regions in books or on websites. Some of those are listed at the end.

Plant Native, an organization based in Portland, OR, is dedicated to using native plants in a more natural way. They offer some excellent guidance on their website along with region-specific plant lists. One particularly useful bit, taken directly from their site, is to realize that …
“…in some instances, human development alters the characteristics of a site such that it may be advisable to use plants from a neighboring region. For example, plantings in urban and suburban areas may receive reflected heat from streets, sidewalks and/or walls or be in media that receives less moisture than normal (e.g., next to a paved area – the pavement blocks rain from entering soil). Accordingly, using plants from a neighboring region that support higher temperatures and/or drier conditions may be more appropriate” (See

Once you have a handle on the area you are working with you need to select the plants to fill the appropriate layers: ground covers, herbaceous perennials and grasses, woody shrubs, small and/or large trees. A typical foundation planting might be modeled on a forest edge or savannah community. Larger or more rural properties may have opportunities to use forest or prairie communities.

An example of a front yard planting modeled on a savannah would consist of some scattered trees like oak or pine under-planted with some shade tolerant perennials and shrubs. Open area would be planted with species preferring full sun. It is important that all the ground spaces be filled to block out weedy intruders.
While you can put together a plant community based on books and websites, there is nothing better than visiting natural sites and seeing some different plant communities. Visiting nearby sites also gives an idea of the native plants that work in your area. Many of the books and websites sited reference examples of places to go to experience these communities first hand (Diekelmann and Schuster’s book lists sites throughout the Northeast US).  Many botanic gardens have examples of native plant communities - and these have labels!  Garden in the Woods, in Framingham, MA and The Lady Bird Johnson Wildflower Center, in Austin, TX, are two of my favorites.

Additional Resources:
Plant Communities of New Jersey, by Beryl Collins and Karl Anderson

Natural Communities of Rhode Island

Classification of Massachusetts Natural Communities

Plant Native Website

Larry Weaner Landscape Associates  Larry Weaner has given some some great talks about work using plant communities.  Check out the website to see where he will be making future presentations.

1 comment:

Dirty Girl Gardening said...

great post... nice info and pics!