Asian bush honeysuckles grow so densely they shade out everything on the forest floor, often leaving nothing but bare soil. This means a great reduction in the food and cover available for birds and other animals.  Serious infestations can inhibit tree regeneration, essentially stopping forest succession.  Some bush honeysuckle species also release chemicals into the soil to inhibit other plant growth, effectively poisoning the soil.  The Asian bush honeysuckles originate in Eurasia (Japan, China, Korea, Manchuria, Turkey and southern Russia).  They were introduced as ornamentals, for wildlife cover and for soil erosion control. However, their aggressive domination of native communities make them a bad choice for these purposes.

Burning Bush can invade not only a variety of disturbed habitats including forest edges, old fields, and roadsides but also in undisturbed forests. Birds and other wildlife eat and disperse the fruit. Once established, it can form dense thickets, displacing native vegetation. It is native to northeastern Asia and was first introduced into North America in the 1860s for ornamental purposes. This plant is still sold and planted as an ornamental.

Japanese honeysuckle is native to East Asia, including Japan and Korea. It was introduced to the United States as an ornamental plant, for erosion control, and for wildlife forage and cover.  Japanese honeysuckle damages forest communities by out competing native vegetation for light, below ground resources, and by changing forest structure.  The vines over top adjacent vegetation by twining about, and completely covering, small trees and shrubs. As it becomes established it forms a dense blanket that endangers most shrubs, herbs, and trees.

Autumn olive is native to China, Korea and Japan.  It was first introduced to United States from Japan in 1830. In Indiana, as in the rest of the country, autumn olive was often used for the re-vegetation of disturbed habitats.  It has also been sold commercially for roadsides, landscaping and gardens.  Autumn olive exhibits prolific fruiting, rapid growth, is widely dispersed by birds and can thrive in poor soil. It has the ability to produce up to 80 pounds of fruit in a single season.  It is vigorous and competitive against native species in open communities like prairies and savannas and re-sprouts after cutting or burning. It also creates heavy shade which suppresses plants that require direct sunlight.

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See Invasive Plant Species Fact Sheet for more information. (PDF)

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How to identify and remove video from YouTube.

Garlic Mustard, Alliaria petiolata, is an aggressive invader of wooded areas throughout the eastern and middle United States. A high shade tolerance allows this plant to invade high quality, mature woodlands, where it can form dense stands. These stands not only shade out native understory flora but also produce allelopathic compounds that inhibit seed germination of other species. Alliaria petiolata is native to Europe and was first introduced during the 1800s for medicinal and culinary purposes.

Japanese knotweed is native to Japan, China, and parts of Korea and Taiwan. It was introduced from Japan to the United Kingdom as an ornamental plant in 1825, and from there to North America in the late nineteenth century.  Japanese knotweed emerges in early spring and grows quickly and aggressively. It forms dense, nearly pure stands which crowd out native plants. By eliminating grasses and other native plants along creeks, the banks are less stable and more likely to shear off during flooding. This greatly increases sediment in the creek. It spreads rapidly through rhizomes and seeds. Fragments are transported to new sites by water and by human interactions. Once established, Japanese knotweed is very difficult to eradicate.

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Here's an article from This Old House on how to eradicate this invasive.

Bradford Pear produce sterile fruits because they do not self-pollinate. They have been widely planted throughout the United States since the early 1900s as an ornamental.  The Callery pear is an invasive species in many areas of eastern North America, out competing many native plants and trees. In the northeastern United States, wild Callery pears sometimes form extensive, nearly pure stands in old fields, along roadsides, and in similar disturbed areas.

Glossy buckthorn is native to North Africa, Asia and Europe. It was introduced to North
America as ornamental shrubs for fence rows and wildlife habitat and is still used in landscaping.  Buckthorn has a wide habitat tolerance, a rapid growth rate and an extensive root system.  It produces abundant flowers and fruits throughout the growing season. Seeds are widely dispersed by birds. They aggressively invade natural areas and form dense thickets eliminating native species. They leaf out very early in the growing season and keep their leaves late into the fall helping to shade out native trees, shrubs and wildflowers.

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See Invasive Plant Species Fact Sheet for more information. (PDF)

Kudzu was introduced into the United States in 1876 at the Philadelphia Centennial Exposition.  During the 1930’s, kudzu was promoted by the Soil Conservation Service and planted throughout the southern United States where it was used for animal feed and erosion control. Since that time period kudzu has invaded the forested lands of the southern US covering millions of acres. In Indiana Kudzu is found primarily south of I-70, but isolated sites have been found as far north as LaPorte, Starke, and Elkhart counties. Kudzu continues to spread further north and adapt to colder climates and is now known to reproduce from seed in the state.  Kudzu out competes native vegetation by shading and using valuable nutrients. It also weighs down trees and increases snow load on trees causing their tops to break. In addition causing tree damage, kudzu mats can be 5 feet deep and impassible leaving many areas unusable for outdoor recreation. Kudzu mats create an ideal environment for rodents and snakes. Finally, kudzu may act as a reservoir for soybean diseases such as soybean rust.

Sicyos angulatus (Bur Cucumber) can create pretty sizable patches.  A cluster of up to 10 capsules form from the female flower heads. Each is almond or egg-shaped, ½ to 1 inch long, covered in stiff spines and long white hairs, and contains a single seed. The color is initially green and eventually turns brown.  Beware of Bur Cucumber fruits—the spines easily break off, embed themselves in skin and clothing, and can be rather painful! 

English ivy, Hedera helix, is an aggressive invader threatening all levels of forested and open areas, growing along the ground as well as into the forest canopy. Vines climb up tree trunks and envelop branches and twigs, blocking sunlight from the host tree’s foliage, impeding photosynthesis. An infested tree will exhibit decline for years before it dies. The weight of vines also makes trees susceptible to blowing over in storms. This plant has been confirmed as a reservoir for bacterial leaf scorch (Xylella fastidiosa), which affects a wide variety of trees.

Palmer Amaranth, Amaranthus palmeri, thrives in hot weather, is tolerate of drought, and responds quickly to high levels of available nutrients. It competes aggressively against warm season crops, and is a prolific seed producer. A. palmeri populations have developed resistance to multiple herbicide modes of action, including ALS inhibitors, triazines, HPPD inhibitors, dinitroanilines, and glyphosate. This plant can have a greatly extended emergence period. Due to this extended emergence period producers must spend additional time and money to manage it.

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