A single look around the Piscataway Park forest and you may miss just how many non-native plants and critters are in view. Upon a closer look, the forests here are full of incredible native plants and animals, as well as many non-native animals and plants. What is a non-native? Great question! A non-native species (plant or animal) is any species that was introduced to a place, purposefully or accidentally, by human beings. For example, corn is native to North America, but non-native in Europe. This means that humans introduced corn to Europe. Another example would be the many species of bees that have been introduced to North America since colonists first arrived. Non-natives are not usually a problem until they start replacing native plants and animals and making it hard for native species to survive.
Any species that invades the ecosystem and space of native species (plant or animal) are considered 'invasive'. An invasive creature or plant comes into the North American ecosystems and takes over, pushing native plants and critters out or even killing them off.
All around you are plants that are not originally from North America. Many of them are even crowd favorites - they were introduced so early in the history of America that many people don't know they aren't native plants. Some even have native cousins, so it can be hard to identify which one you have found. Explore this list below and see if you can discover which of these plants are native, non-native, and/or invasive. A few might fit into more than one of those categories.
Dandelion
Scientific Name: Taraxacum officinale
Common Name: Common Dandelion or just Dandelion
Native to Europe and Asia, originally brought to America as a food crop in the 1600’s.
Known for its brightly colored yellow heads
Commonly considered a weed, most often found in lawns and along driveways/walkways.
The leaves, flowers, and roots are all edible and can be used in medicines.
These non-natives enjoy open spaces and grow well in soil that is lacking in nutrients. Can often be found growing at construction sites.
The deep taproot pulls nutrients from lower soil layers to the top, making it easier for plants around it to get the nutrients they need.
Does not fight with native plants for food or space.
This is a low-growing, groundcover.
Honey Suckle
Scientific Name: Lonicera japonica
Common name: Japanese Honeysuckle
Originally from Asia, introduced to New York in 1806 as a garden plant and to help prevent soil erosion on edges of forests/shores.
There are many different types of honeysuckle, but almost all of them are not native to America.
Reproduces both by seed and through runners that will root into the ground and sprout new plants.
Honeysuckle is a climbing vine, growing on top of other plants and climbing up trees. It creates a dense canopy once it is well rooted, making it difficult for plants below it to get sunlight.
Grows mainly on low lying trees and bushes. Found most commonly at Piscataway Park in the blackberry brambles.
This plant is best known for its vibrant flowers. Many people think of honeysuckle and think of eating the nectar from the flowers. Japanese Honeysuckle is mildly toxic, but the flowers can be eaten and were for many years by those living in the area.
Deer enjoy eating all honeysuckle varieties, enjoying the young vines and flowers.
Tree of Heaven
Scientific Name: Ailanthus altissima
Common Name: Tree of Heaven, China Sumac, varnish tree
Native to China, this tree was introduced to the United States of America in the late 1700’s
A fast-growing deciduous tree, grows to be up to 80 feet tall and 6 feet in diameter. Fills in the upper canopy of the forest.
All parts of the tree smell like rotten peanut butter – not a pleasant smell
Looks similar to native trees such as the Black Walnut and Sumac trees in leaf shape, number, and style.
Introduced as an ornamental, the tree of heaven quickly spread to grow anywhere. It crowds out native plants and competes with them for sunlight and nutrients.
If cut at the root and the roots left in the soil, it will re-sprout from the root. The tree also sends out runners as much as 50 feet from the original tree, which will sprout a new tree.
Seeds are called Samaras, and will spread as the wind blows them loose from the tree. The tree produces hundreds of seeds, which allows this tree to spread quickly.
Host plant for the Spotted Lanternfly, an invasive pest from China. Click here to learn more about them.
This tree can emit chemicals from its roots, leaves, and bark that will cause other plants to die if they are growing too close to the tree. This is particularly an issue for native plants.
What can be done about invasive plants? Are all of the plants listed above invasive? If so, how are they hurting the native plants or ecosystems they live in? Is there any way to reverse the introduction of these plants - remove them from the ecosystem? Should humans try to remove invasive plants, or will that just mess up the ecosystem more?
At the Accokeek Foundation, we understand the important role humans play both in introducing invasives, managing them, and preventing future introductions. We keep in mind the 4 R’s when dealing with invasive plants.
Recognize
Identifying the invasive plant is important. Some plants, like the Tree of Heaven, look a lot like native plants. Be sure to use a guide to identify the invasive, just to make sure you are pulling the right plant. Check out these resources from iMap Invasives and DNR's Invasive ID cards.
Remove
Pull the plant by hand and be sure to remove the entire plant (including roots). Make sure to know if you are allowed to dig in your area - some places, like Piscataway Park, try to limit digging to not disturb the soil. Many invasive plants can regrow if pieces of them are left behind. If you can't remove the whole root,
Be sure to wear proper gloves, long sleeves, and use tools. Be careful removing plants like Stinging Nettles, which can sting or injure you if you aren’t wearing proper protection.
Dispose of the plant pieces in the trash – don't compost them or burn them. Some parts of invasive plants are toxic, or will grow again if put into a compost bin.
Replant
Fill the space you’ve just cleared with native plants that belong in that ecosystem. If you remove a plant like the Tree of Heaven, plant new trees to fill in that space. Otherwise, other plants will move in and you may have more invasives than before. Check out the National Audubon Society's Native Plant Database for ideas.
Revisit
Check that spot regularly to make sure invasive plants haven’t moved in again.
Check on the plants that have been replanted to make sure they are growing well.
Not all plants that have been introduced by humans to a new environment are invasive. Some of those plants are even healthy additions to the biodiversity of that region. However, it is important to realize the role all of us can play in the introduction of new species into native habitats. Accident or not, we should be aware and take precautions to avoid spreading plants that are non-natives without weighing the possible impact of those plants on the new space. Invasive species can be prevented, if we're willing to think ahead and make wise decisions. The question is not 'will we shape the land', but 'how will we shape the land'?