Importance of Native Plants
Native plants are, in a word, local. They are plants that have been growing in a particular habitat and region, typically for thousands of years or longer. Also called indigenous, they are well adapted to the climate, light, and soil conditions that characterize their ecosystem.
The native ranges of plants vary. Woody plants are typically indigenous to substantial portions of our continent. Northern Red Oaks, for example, are native from Nova Scotia, southern Ontario, and Minnesota, through the eastern and central U.S. to Georgia, Mississippi, and Oklahoma. Yet, not all ranges are this big. Rhodora, a beautiful, bog-loving azalea, is native from Labrador and Quebec, south to the mid-Atlantic states. A few unique and rare plants are even more specialized and indigenous to quite small regions.
In Massachusetts, we consider all the plants that grew here prior to European colonization to be native. They evolved slowly over time with relatively little interference from humans, although they were an important part of Native American life. These were the only plants growing here before settlers began introducing non-native plants from other continents, expanding agricultural practices, and manipulating the genetics of plants through cross-breeding and now, bioengineering.
Native plants are important as they provide the foundation for healthy ecosystems. If they are properly sited for their desired soil and light requirements, they can require less water, fertilizer, and maintenance to thrive.
The fruits and berries of native plants are critical to bird life, and provide approximately 40% of the avian diet as a whole. When birds eat these fruits, the ecosystem gets the benefit of seed dispersal, as the birds excrete the seeds in their droppings. A reasonable number of these will germinate and that plant species is sustained from generation to generation. Unfortunately, if the bird eats the fruits of an invasive plant, it spreads these undesirable plants further and further afield, and because of their aggressive ability to outcompete other plants, the invasives continue to take over and damage the ecosystem even further.
What might surprise you about native plants is that they are especially important because of the insects they host. We humans have been programmed to think otherwise, but insects are critical to our ecosystems and therefore to us. On the whole, insects and other arthropods provide about 60% of the avian diet. And they are absolutely critical to the nestlings of terrestrial species as virtually their sole food source. So without insects, our beautiful songbirds couldn’t survive or raise their young. Without caterpillars, there would be no butterflies. Without ponds and vernal pools teeming with insect life, there would be no spring peepers or amphibians. Insects are one hub in our web of life, critical intermediaries between plants and the animal world
Native plants are host to a vastly greater number and variety of insect species than are non-natives. According to entomologist Douglas Tallamy, author of Bringing Nature Home, our native flowering dogwood (Cornus florida) supports one hundred and seventeen species of moths and butterflies, while the non-native Kousa dogwood hosts only six species of insect herbivores. The Golden Rain Tree (Koelreuteria paniculata) from China supports one caterpillar species, while our native oaks can host 534 species. And if those caterpillars don’t make it into beautiful butterflies or moths, all make good bird food. Tallamy can cite example after example, summarizing his years of extensive research, and concluding that “native ornamentals support twenty-nine times the biodiversity of
alien ornamentals.” And these insects are not to be feared, because in a balanced ecosystem, they nibble small enough portions of the plants available so that we hardly notice their presence.
So there we have it. Plants provide the foundation for life by capturing the energy of the sun and converting it into biomass for the rest of us to eat, and native plants promote the biodiversity necessary for balanced ecosystems. If we want a sustainable future, it is time to pay attention to the importance of growing natives. Further information on native plants can be found here.
A complete list of native plants in Wayland can be found here and a list compiled from Mass Audubon can be found here.
Non-native or “exotic” species of plants that are introduced into new ecosystems, i.e. to regions of the world where they have not lived before, may or may not become invasive. Some scientists estimate that about 25-30% of the non-native species that have been introduced to the United States have now become invasive.
Invasive plants, essentially, are species that grow very rapidly and out of control. Away from the diseases and predators that helped to keep them in check in their home environments, they are able to grow and reproduce so aggressively that they quickly out-compete native species—damaging the ecosystem because their dominance reduces biodiversity—eliminating many of the plants and animals that used to live there. Often, they spread extensively enough to form “monocultures,” or areas where they literally are the only plant growing.
Just as not all native plants have the same range, a particular exotic or introduced species might be invasive in one part of the United States but not another. Or it may take some time for that species to get established in different regions, so it may already be invasive in one area or state, but not yet have had the same impact elsewhere. Because our study of invasiveness is relatively new, and plants constantly continue to colonize new areas, it is quite likely that the range within which any given introduced plant species is recognized as being “invasive” will grow over time. Further information can be found on Grow Native Massachusetts or from SuAsCo CISMA.