A First Step Toward Sustainable Landscaping

In recent years, our Garden Management clients have been asking: What can we do to move in the direction of sustainable landscaping? The question revolves around our shared desire to have a sustainable landscape–one that is beneficial to living things (including soil microbes) and doesn’t adversely affect the surrounding ecosystem.

Interest in this question is ongoing and evolving, and we see the concept of sustainable landscaping as the sum of four principal components in the total picture:

1. soil health
2. plant selection
3. plant care practices and materials
4. hardscape design and materials

We thoroughly covered soil health, the first and most important component of sustainable landscaping, in two previous articles: Soil Health & the Role of Garden Maintenance and Healthy Soil: The Foundation of All Your Landscaping Efforts.

So for this article, we will focus on the second most important component, landscape plant selection. Plant selection is critical because striking a balance between native species and ‘exotic’ (a.k.a. introduced species) in our landscapes and gardens really is the starting point for everything that happens afterward.

Sustainable Landscaping Begins with Plant Selection

When developing the initial planting plan for your property, our garden managers recommend that you incorporate as many native plants as possible into the design. At least 50%. Of this 50% or more, trees and shrubs are the most important category because they are the foundation of the landscape. They will last the longest and be potentially the most beneficial to wildlife in the existing ecosystem. Also, and some people may not want to hear this, keeping lawn area and therefore lawn maintenance to a minimum is highly recommended.

Native plants naturally provide the food and shelter needed by beneficial insects, birds, pollinators, and other wildlife at the right times of year. In addition, native plants conserve resources. They cut down on the need for surplus watering and pest management because they are adapted to the existing environment including weather patterns, pests, and existing soils.

Native, Non-Native, and Exotic Plants

So the first thing you need to know is that the plants, shrubs and trees used in residential landscaping and in many public spaces fall into three broad categories: native plants, non-native plants, exotic plants, and cultivars of both natives and exotics. Here are the simple definitions.

Native Plants
A native plant is one that is indigenous to a local habitat. It plays a specific functional role in an ecosystem that has evolved over hundreds or thousands of years in a particular geographic region.
Non-native Plants
This would typically be a plant that is transported, usually due to human activity, from one local or regional environment into another where it would not naturally find a home.
Exotic Plants
Exotics are specimen plants that are brought from one continent to another, sometimes by accident, but most of the time intentionally. In the U.S. we have become accustomed to using many exotic plants that are native to Asia or Europe in our landscapes.

There is another class of plants called “invasives.” These are typically exotic or non-native plants that take over a local habitat, aggressively crowding out other species and reducing biodiversity.

Invasive Species and the Big Takeover

When selecting non-natives or exotic species to fit your sustainable landscaping plan, avoid known invasives that aggressively take over naturalized areas. We’ve seen garden plants that were popular in people’s yards jump into the nearby woodlands or fields and overrun the existing species. This is bad because invasives often do not contribute food and shelter for wildlife including insects, pollinators, and birds. Instead, they take over and choke out plants that do provide sustenance.

Out on a walk, have you ever seen English ivy covering a forest floor, preventing the next generation of tree seedlings from sprouting? Or have you seen the ivy cloaking a once healthy tree and shading it to death? This is an example of an invasive plant species. It may look nice climbing the brick chimney of a Tudor style home, but once it escapes your yard–it’s trouble. When birds and pollinators don’t have the quality of food and shelter they require, your landscape will eventually suffer the consequences as well.

Here are two examples of once popular trees and shrubs that were sold in garden centers for years before we realized the harm that they are capable of:

Invasive Trees: Bradford Pear
Bradford pears trees are fast growers that flower prolifically and are quite attractive.

Which is why they became so popular–and ubiquitous. The problem we found is because they are such fast growers, they reproduce rapidly and can take over the edge of forests where there should be rebuds, dogwoods, and service berries. They crowd out everything else and knock out the diversity of an entire area.

Invasive Shrubs: Burning Bush
Burning bush is another type of invasive that you will see coming up in woodland areas and regional parks. It produces a berry that birds eat and spread throughout the forest in their droppings (like the Bradford). A good substitute for burning bush is the blueberry. It is of similar size and has a beautiful fall color like the burning bush.

This is not to condemn all but those species native to our Northern Virginia area. however, it is important that you carefully evaluate the characteristics of plants you are introducing into your gardens -and potentially- the surrounding woods and fields. The Ecological Landscape Alliance offers an excellent explanation of the differences between native plants and invasive plants, and why those differences matter.

Aesthetically, exotics make a terrific contribution to the overall picture. They are interesting, unusual additions to any landscape and there is certainly a place for them in your sustainable landscaping plan. But the rule of thumb is to have two-thirds of your landscape planted with native varieties. Or as stated above, 50% at the minimum.

Sustainable Landscapes Support Life

Keep in mind that our backyards are part of the larger ecosystem. They affect it, and we should incorporate as much of the natural ecosystem in our yards to help sustain it. Practicing sustainable landscaping means being a good steward of the environment, being a responsible actor in the ecosystem of which we are a part. Our landscapes contribute to our quality of life. The more sustainable the landscape, the more life there will be in it. That’s the difference between a still life landscape–which is nice to look at but… and a landscape that is active and full of life.

Perhaps you’ve been wondering how to bring out the fullest expression in your landscape and gardens. Our eBook: Choosing the Right Kind of Landscape Maintenance Firm, is full of valuable information to help you understand the fundamental differences between landscape maintenance companies.

All images ©Morgan Howarth Photography except as noted.