Natives or Non Natives?
ARE NATIVE PLANTS ALWAYS A BETTER CHOICE?
Native plants are often talked about among gardeners. Many of us believe that natives are better ecological choices and are more beneficial in providing habitat for native wildlife. Contrary to popular belief, research shows that the “native” status of trees and shrubs has little influence on biodiversity.
Many also believe that native plants are always a better choice because they are adapted to local growing conditions. Claims are made that native plants are superior to introduced species in their ability to withstand local climate conditions, to resist pests and disease, and to require less fertilizer and other forms of maintenance. None of these claims are supported in published research when speaking about home gardens and landscapes.
First and foremost, trees and shrubs that survive and thrive, regardless of their native or non-native status, provide the greatest benefit to native wildlife. If a native tree or shrub is planted, and because of its environment, dies, it provides no benefit to native wildlife.
How closely do our urban and suburban landscapes mirror the conditions that native plants require? Here are some facts about many of our home landscapes:
Urban/suburban soils consist of layers of ‘topsoil” and other materials; usually clay, creating poor drainage and low oxygen levels.
Urban/suburban soils are consistently compacted because of foot and heavy equipment traffic.
Urban/suburban soil PH is high due in part, to leaching of lime from concrete.
Urban/suburban hardscape surfaces reflect heat and light which doesn’t happen in nature where hardscape surfaces aren’t present.
It is obvious that our neighborhoods don’t often resemble what existed prior to development. With this reality in mind, it is understandable why some of our native plants no longer survive or thrive in our non-native environments.
The question then becomes does the use of non-native trees and shrubs reduce the food and shelter available to beneficial wildlife? Research reveals that, with few exceptions, the native status of trees and shrubs has no impact on wildlife biodiversity. Having a diverse assortment of plants with different structures and forms was the most important factor to enhance and encourage wildlife biodiversity. Native species can be part of this assortment but we need to remember that the ability of native plants to live in our home landscapes is determined by the environment they are placed in, not by their genetics.
When choosing plants for your home landscape, keep these items in mind:
Actual site conditions should determine plant selection.
Choose woody trees and shrubs adapted to the alkaline, compacted, and poorly drained soils in most of our neighborhoods, regardless of their native or non-native status.
In areas with higher levels of reflected sunlight or heat, choose plants adapted to hot, dry climates.
Reduce open lawn area and add vertically diverse plants.
Increase tree and shrub cover as wildlife seeks out protected vertical spaces for food and shelter.
Protect soils with woody mulch, especially in compacted soil areas. Woody mulch improves the soil and provides habitat for insects, reptiles, and small mammals.
Native plants may be a good choice for urban settings but only if the actual site conditions will allow them to live and thrive. In many cases, non-native plants, more suited to the actual conditions of an urban landscape, may be a better choice for you and for the wildlife that needs the shelter that both native and non-native plants provide.
