Ginger Woolridge, co-author of Essential Native Trees and Shrubs for the Eastern United States discusses the importance of planting native for the sake of indigenous plant and animal life.
Natives play an elemental role in our terrestrial ecosystems, but the majority of plants sold in our nurseries - today - are non-native.
We are naturally drawn to the new, the different and the exotic. Since the early 1600’s, we have been importing plants from Europe and from Asia through Europe. But today, in the planted landscape, the population of natives is overly diminished. The majority of plants sold in nurseries are non-natives – a situation that does not bode well for our native insect and bird populations.
The most logical reason for embracing our native plants is to support the food web that has evolved in the Eastern US through the millennia. Healthy native bird populations require healthy native insect populations and healthy native insect populations require healthy native plant populations. Here is how it works. Plants protect themselves with naturally produced toxins. Insect larvae usually specialize, having evolved with a tolerance for a particular species of plant. For instance, monarch butterfly larvae require milkweed species foliage. In turn, these insect larvae are the perfect food for birds, especially baby birds. The soft, protein and fat laden larvae provide critical nutrients for nestlings; they are fed hundreds of them per day. Introduced plants provide far less nutritional support. These relationships are logical and universal, but rather invisible to most folks, even gardeners.
Fortunately, a growing awareness of the need to support our native food web is evolving.
Insect populations are in decline, most apparent using what some call the “windshield test.” You may remember when gas station attendants would scrub bugs off of the windshield of the family car. Summer street lights would attract loads of moths and other nocturnal pollinators. Researchers here and in Europe are noting a troubling decline in the number and variety of insects.
Our native plants are threatened in several ways.
- Fragmented landscapes result from sprawling development and remaining natural areas can be too small to sustain our native species
- Many of our developed areas and even forests are over-browsed by deer populations that are out of control
- Invasive plants often compete with natives since are not exposed to the predators, disease, and competition with which they evolved. The most invasive plants are usually non-native, such as kudzu, Tatarian honeysuckle, Russian olive, English ivy, liriope, vinca, and Japanese barberry, Japanese stilt grass
- Global warming stresses native plants with increased temperatures, longer periods of drought, and more irregular and powerful storms
- Non-discriminate use of herbicides can kill native plants when other “pest” plants are targeted. Insects face a similar issue with indiscriminate pesticide use
Natives provide important critical ecological services to keep an ecosystem vibrant. Their essential role in our terrestrial ecosystems includes many connections that we do not yet fully understand and exist on macro and micro levels.
It all seems terribly depressing; but, there is good news.
The Eastern US has a terrific palette of plants. In fact, while we have imported plants from Europe and Asia, they have been importing ours – another indication that we are drawn to the exotic.
Our diverse group of native trees and shrubs provide the architecture for many types of plantings. A plant exists for almost any situation or requirement. These plants can be used in formal or naturalized settings, as woodland edges, in street plantings and rain gardens, for irrigated roof gardens, screening, hedging, as woody ground covers, woodland edges, flowering, autumn color and so on.
When our natives are planted in appropriate environmental conditions - clearly defined in Essential Native Trees and Shrubs - they are tough. Once established, many are tolerant of difficult situations including drought, shade or full sun, moist to wet soils and salt spray. Most of the plants grow successfully in USDA Zones 5-8.
Natives are economical. They usually require less investment in maintenance – less water and fewer fertilizers, herbicides and pesticides.
Among other services, trees and shrubs provide climate modification (cooling and shade), energy conservation, improved air quality, reduced runoff and flooding, and wildlife support.
Some natives are especially productive in terms of larval support. These include oaks, willows, and cherries. With the built environment outpacing land preservation, it is incumbent - on those who understand ecological processes - to do what we can in our gardens, our neighborhoods and our towns.
To be clear, we do not necessarily advocate for a 100% native garden. Personally, I enjoy my boxwood and peonies too much! But, I am also crazy about my sourwood, walnut, old beeches, southern magnolias, hemlocks, sweetbay magnolias, dogwoods, redbuds, deciduous azaleas, rhododendrons, oakleaf and smooth hydrangeas, fothergillas, witch hazels, spicebushes.
We would like to encourage designers and home gardeners to increase their use of natives.
We hope Essential Native Trees and Shrubs for the Eastern US can help you choose plants efficiently and confidently.