Humans are dependent on plants. Plant fibers provide clothing, building materials, and paper. Fruits and crops feed humans and livestock. Old and new, plants provide fuels like coal and ethanol. Plants are processed for medicines and industrial products as well as for perfumes and cleaning supplies. It’s hard to think of a product used in daily life that does not rely on plants.
Many of the benefits of plants are free of charge and invaluable to human life. Plants are responsible for the oxygen we need to survive, and they also help clean the air we breathe, improve water quality, prevent erosion, buffer climate change, and provide habitat for wildlife. Plants beautify our surroundings for recreation, relieve our stresses, and offer us a great view.
Each of the plant species we use is native to somewhere in the world, is adapted for that environment, and is often part of a specific ecosystem composed of other plants or animals. If we lose one native plant species, we may risk losing the other species that depend on i--as well as the benefits it and the other species provide us. When we introduce a new species, we may gain some new benefits but also may harm some of the plant species we already value.
Protecting native species and the benefits they provide is not difficult when each of us recognizes that we can all be good stewards of the land on which we live. Maintaining a diversity of native plants in the environments for which they are adapted helps promote the longevity and the benefits of native ecosystems.
Why does it matter whether or not you use native plants in your landscape?
A staggering one-third of U.S. birds are in danger due to native habitat loss. Native bird populations and their habitat companions will continue to decline unless we restore the native plants they need for survival in our suburban ecosystems. It’s not too late, and fortunately, restoring native plants in a human landscape is easy to do.
Douglas Tallamy, professor of entomology at the University of Delaware, teaches that all plants are not created equal, particularly in their ability to support wildlife. Most native plant-eaters, especially beneficial insects that are food for native birds and other wildlife, are unable to eat non-native plants such as alien honeysuckles, non-native maples and a long list of others. Why is this? Through millions of years, plants and animals have co-evolved, changed, and adapted, resulting in beneficial relationships that allow co-existence, in balance, in the web of life. This means that native insects eat native plants; the native insects are then eaten by the native birds, and so on.
Most non-native plants were introduced to this country in part due to their pest-free garden success, and many have next to no value for the native insects and birds that eat them. Tallamy asks, “Rather than plant a species that has little to no value for native insects, birds and wildlife, why not plant native species that support up to 30 times more species in the food web?”
An example of a tree that has not co-evolved with North American insects, birds and wildlife is the Norway maple. Introduced to the Philadelphia arboretum in 1756, this large shade tree has in its 250 years on the continent provided little or no benefit to native insects and birds compared to native maple trees. However, the Norway maple now displaces native trees in several habitats.
What you can do to introduce native plants
- Reduce the turf footprint in your yard and plant native species in groupings. A perfect place is along a fenceline, a privacy hedge, or an existing woodland edge.
- Include vertical layers in the plantings: trees, shrubs, wild flowers, grasses and sedges. Native fauna depend on the layers from the ground to the tree canopy.
- Plantings in wide groups provide better shelter and breeding habitat for common native bird species. Longer and wider is better, and so are non-linear edges.
- Provide organic wood mulch to the whole grouping of plants. Allow leaves to remain on the ground where they fall in non-turf areas—just like nature.
- After decades of insect and bug phobia, we can adapt our landscape maintenance to tolerate beneficial insects feeding on our plants. Remember, most insects provide important food for birds and a host of animals.
- Learn the alien insects that threaten our native plants, and target control measures only to specific pests known to be harmful. Use pesticides only as a last resort.
- Plant natives as though life depends on it—it does!
Did you know?
- By planting a wide diversity of native plants, you can support more species in your home habitat and minimize the effects of a pest outbreak.
- Nearly all upland nesting songbirds rear their young on insects and caterpillars, not seeds or berries.
- Most insects are specialists, eating only one related group of plants. Fewer insects are generalists, eating many species of plants.
- Plants can tolerate some insect feeding. Healthy plants can withstand up to 30 percent defoliation without causing stress.
Examples of beneficial native plant and insect relationships
Monarch butterflies feed and lay eggs on native milkweed plants, and Monarch caterpillars also feed on milkweed. The milkweed’s “milk” (white latex) contains toxic compounds that are somewhat poisonous to many animals. Because the monarch species has co-evolved with milkweed, it absorbs and tolerates these substances. The toxins in the caterpillar and butterfly have become a survival mechanism, since it tastes awful to predators. Other butterflies have adapted colors to mimic the monarch and discourage predators—a bird will think twice before eating a viceroy butterfly, since it closely resembles the monarch.
Native oak trees have wildlife value that cannot be overstated. Acorn forage is essential for sustaining a long list of wildlife species over winter. Oaks provide leaf forage for 517 species of native moths and butterflies whose caterpillars are essential for native bird survival.
American basswood trees produce an abundance of nectar, attracting bees that make it into some of the highest value honey. In some parts of its range the basswood is known as the bee tree. With more natives come more bees for pollination in our gardens and landscapes.
|Common name||Scientific name||Moth and butterfly species supported|
|Black cherry||Prunus serotina||448 (all 3 species)|
|Choke cherry||P. virginiana|
|American plum||P. americana|
|Paper birch||Betula papyrifera||413 (all 3 species)|
|River birch||B. nigra|
|Yellow birch||B. allegheniensis|
|Poplars (aspens & cottonwood)||Populus sp.||368|
Table adapted from Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens by Douglas Tallamy, p. 126.
|Common name||Scientific name||Plant type and approximate height|
|Alien honeysuckles||Lonicera tatarica, L. morrowii, L. maackii, L. X bella, L. fragrantissima and others||Shrubs (approx. 10 feet)|
|Norway maple *||Acer platanoides||Tree (40 feet)|
|Amur maple *||Acer ginnala||Small clump tree (20 feet)|
|Oriental bittersweet||Celastrus orbiculatus||Woody vine (50 feet)|
|Japanese knotweed||Fallopia japonica||Huge perennial (10 feet)|
* Consider removing if near a woodland where its seedlings can reproduce.
Visit the DNR website to read about other terrestrial invasive species in Minnesota.