Growing Native Plants to Thwart Invasive Species
By: Ryan Reed, Natural Resource Program Specialist, Bureau of Forestry
It is no coincidence that most areas infested with invasive species are those places where humans have significantly altered the landscape through clearing and earth-moving activities. Such activity typically destroys the existing native plant community and supporting soil structure, while also creating a void for invasive plants to easily fill. Replanting native plants can and should be used in the fight against these prolific non-natives. It is interesting to note how few (if any) invasive plants exist in undisturbed environments like mature forests. These growing sites are already occupied and continuously subjected to seeding cycles of the dominant native plants nearby. The ecosystem in turn supports and assists native plants in establishing future generations through seed dispersal, pollination, and other beneficial interactions. If we want to get the upper hand on invasive plants, then we need to take a page from nature and restore our native seed source plants to a dominant status in our manipulated landscapes. Doing so will help to restore a functional ecosystem. Amazing things begin to occur when you plant native plants. Fewer invasive species will populate these restored areas, and suddenly, native pollinators like butterflies, hummingbirds, and moths will visit your land. Some insect pollinators may even take up residence for quite some time on your property -- completing all or part of their annual life cycle (like monarchs, for instance). With new native insects in the fold, their appropriate native bird predators will also follow, gobbling up larvae to feed their nestlings. The nestlings may grow up to feed on some of the native seeds in your native garden, and spread them far and wide while foraging in other places, creating a cycle that can eventually lead to a sustainable source of native seeds and the plants that come from them. To become sustainable, this process likely requires our native plants to greatly outnumber the invasive ones, though. Every disturbed land should be viewed as an opportunity for restoration of native plants. Perhaps there will come a day when complete restoration to a native habitat will be the standard, rather than planting some grass and a few non-native trees. A few governing bodies throughout Pennsylvania and surrounding states already incorporate this ethic by policy or ordinance, mandating that replanting efforts include native plants; but more is needed. There seems to be a growing tide of momentum and interest in the native plant movement. Native plant sales abound in the spring, more native nurseries seem to crop up almost overnight, and these enterprises are certainly gaining popularity. The prospect of out-competing invasive species by planting natives on a large-scale basis is not realistic if there is not enough human participation. For true ecological restoration to occur, native plant networks must be formed, entailing private residences and developments, golf courses, industrial complexes, community parks, and other open lands. With spring finally here, it’s a great time to begin planning your native planting. Your contribution, however small, will help in the fight against invasive plants in the long run!
Landscaping with Native Plants
A native plant is one which occurred within this region before colonization by Europeans. Native plants include Ferns, Club mosses, Grasses, Sedges, Rushes, Wildflowers, Woody trees, Shrubs, and Vines.
There are approximately 2,100 native plants in Pennsylvania. An introduced or non-native plant is one that has been brought into the state to become established in the wild.
At the turn of the 21st century, about 1,300 species of non-native plants existed in Pennsylvania outside of gardens, parks, and agricultural lands. That is 37 percent of Pennsylvania’s total wild plant flora. More introduced plants are identified every year.
The use of native plant species offer many advantages to using non-native species.
• Adapted for Local Climate and Conditions: Native plants are adapted to local soils, climate, and conditions and will persist through frost and drought.
• Bird Food: Native plants provide seeds, insects and caterpillars.
• Pollinators: A planting of native plants will attract native pollinators such as native bees, butterflies, moths, beetles, and hummingbirds. The DCNR Bureau of Forestry promotes and tracks pollinator plantings (PDF).
• Low Maintenance: Native plant species require less maintenance such as water and soil amendments. Once the plants are established they will require little else.
• Maintaining Native Biodiversity: Native plants experience multiple threats such as habitat conversion, invasion of exotic species, deer herbivory, pollution, and over collecting. By using native plant species you can help to maintain the native biodiversity of Pennsylvania.
Tips for Landscaping with Native Plants
~ Minimize habitat destruction. First, conserve existing native vegetation and plant communities. Minimize habitat disturbance. Ecological restoration may be necessary, including native plantings, invasive removal, erosion control, or loosening soil compaction.
~ Use native plants. Well-chosen native plants can flourish in public and private landscapes. Avoid rare plants and choose common native plants. If you must use non-natives, choose plants that will not escape and become weeds.
~ Learn more about native plants. Learn what plants are native in your area. There are many field guides to wildflowers that can get you started.
~ Buy nursery-propagated native plants. Most retail nurseries and mail-order catalogs now offer native plants. There are also a number of native plant sales held in the spring.
~ Do not remove native plants from the wild. Taking native plants from the wild depletes native populations. Also, many wild-collected plants do not survive transplanting. Prevent wild-collecting of plants by making sure that plants you buy are propagated at a nursery.
~ Practice responsible landscaping techniques. Choose the right plants for the site: wet or dry, shade or sun, acid or neutral soil. Learn to identify the local plants to guide plant selection. Plant nurseries, catalogs, books, or online information can help too. Also limit fertilizer and pest chemical usage.
Never plant invasives!