The topic of native plants is extremely popular in gardening communities. Those in favor are often extremely vocal, even adamant, about what they have learned online and from hearsay. We hear the same “facts” over and over and most people start to believe that they are true. They may not be. The study of native plants and their relationship with native fauna is fairly recent and somewhat limited.
It does not help that universities have joined the discussion to drum up business and to stay relevant. Online content, even from sources like Native Plant Societies and the National Audubon Society sometimes provide questionable information.
The National Wildlife Federation online plant finder tool is an example of native plant recommendations gone wrong. Enter any zip code for your state and you will get all the same results (all plants listed for the state), regardless of your location. It lists almonds as native to New Jersey.
Are plants that are native to a state actually better for home gardens in that state?
Plants are native to specific ecosystems or a habitats, not to a state. They just happened to have been observed in that state. A state may have those habitats, but they will not be in every part of the state.
Before discussions got muddied up, involving the home garden, the concept of planting native plants was to repopulate their natural habitats in order to boost declining species and biodiversity. However, an urban, suburban or even rural home garden is not a natural habitat. Everything natural living thing was removed during development, including some of the soil. After construction, topsoil was trucked in from somewhere and lawn was planted. This habitat is closer to a disturbed area or a roadside, than a wood, meadow, marsh, etc.. So what plant is native to this habitat?
A home garden also has a house in it. A house with concrete sidewalks and a paved driveway, all of which add heat, light and all kinds of human stuff. Plus a wide, paved street and neighbors all around for more heat and human stuff. Are those the conditions the native plants grew in 100 years ago? Definitely not.
The soil I started with was clay and rocks. Was this the original native soil or what the homebuilder trucked in from elsewhere? Is it the right soil for native plants? I have full sun, but many gardens in the same zip code are in almost full shade. I can grow natives that other gardeners in my area cannot. What does this experience say about native plants that many claim to be better for the environment because they require less care, water, etc.? It’s simply not true.
In terms of less care, to minimize environmental impact, what gardeners need to be planting are species (native or otherwise) that do well in the existing conditions. If a garden is baking in the sun, a native plant that likes cool, moist conditions is not going to do well.
The choice of plants depends on the gardener’s objectives. If it is to host a collection of native plants, she will have to ensure that the plants are given the right soil, light and moisture, which may cause the garden to be high maintenance and high environmental impact.
If the objective is to breed native wildlife, it helps to know which specific plants they need as hosts for their larvae. Not all native plants host specific insects. Very few gardeners know any host plants other than milkweed. Milkweed is not a plant, it is a common term that covers a wide range of plants that show white sap when injured. They look different, require different growing conditions and not all are native.
Some will tell you that native plants and insects evolved together, so the best food for native insects is from native plants; that the food they get from non-natives is equivalent to candy. There is insufficient evidence to support this theory.
There is, however, scientific evidence that non-native plants can be more attractive to insects both native and otherwise.