Bush Honeysuckle
Bush Honeysuckle (Lonicera maackii), also known as Amur honeysuckle, is one of the most destructive invasive species in the St. Louis region. The Garden recently created a new bush honeysuckle brochure to increase public awareness of this issue and encourage citizens of our region to take notice and take action. This page on invasive bush honeysuckle provides complimentary information for the brochure, including expanded content on its origins and impacts, detailed instructions for control, native plants that are similar in appearance, and suggested landscaping alternatives.
 
Honeysuckle History

Origin, History and Invasion

Bush honeysuckle, also known as Amur honeysuckle (Lonicera maackii), is native to far eastern Asia, primarily in China, Russia, Mongolia and North Korea. It was collected in 1855 by the Russian botanist Richard Maack, whose surname is the basis for the scientific name of the species, Lonicera maackii. As early as 1883, it was cultivated at the St. Petersburg Botanical Garden in Russia, and further shared with botanical gardens and nurseries elsewhere in Europe.

In the final years of the 19th century, bush honeysuckle was introduced to botanical gardens in North America via the exchange of seed with European botanical gardens. From 1960-1984 the US Department of Agriculture promoted bush honeysuckle and developed so-called “improved” cultivars, selecting for traits such as increased fruit production that further contributed to its invasive potential. It was planted for wildlife habitat and erosion control, though it is poorly suited for those purposes. Bush honeysuckle’s popularity as an ornamental plant was the primary source of its invasion.

As early as the mid 1920s its escape from cultivation was documented near the Morton Arboretum outside of Chicago, though it became increasing popular as an ornamental plant for many decades afterwards, especially the 1950s through the 1980s. Beginning in the 1950s, its escape from cultivation and invasion became more widespread in states further to the east. In Missouri, it wasn’t documented outside of cultivation until 1983, when it was collected in a St. Louis rail yard. Bush honeysuckle has now spread throughout much of the state, but is most concentrated near urban areas 

For more information on the origin and invasion of bush honeysuckle, see: Amur honeysuckle, its fall from grace: Lessons from the introduction and spread of a shrub species may guide future plant introductions.

Impacts of Invasion

Native Plant Diversity: Woodlands invaded by bush honeysuckle have dramatically reduced diversity and abundance of native plants compared to uninvaded woodlands (2, 3, 4), and severe infestations develop into impenetrable thickets in which native plants are almost completely eliminated.

Forest Health: Bush honeysuckle invasion also inhibits the survival and growth of tree seedlings in woodlands and forest (3, 5, 6), and even reduces the growth of mature canopy trees in hardwood forests (7). This invasion threatens the very future of Missouri’s forests, which will not persist if mature trees die without replacement. Approximately one-third of Missouri is covered by forested land, and the timber industry creates thousands of jobs and contributes about $3 billion each year to Missouri’s economy (8).

A Competitive Advantage: Bush honeysuckle is one of the first plants to leaf-out in the spring, and is among the very last to drop leaves in the fall. This gives it a competitive advantage and allows it to shade-out native vegetation (4). The roots, fruits, and leaves of bush honeysuckle contain chemical compounds that inhibit seed germination (9, 10, 11, 12), further threatening the persistence of native plant populations. 

Pollinators, Insects, and Amphibians: Many native insects require the presence of specific native plants to complete their lifecycle, such as the well-known dependence of Monarch butterflies on native milkweeds. Similarly, the larval host plants of the beautiful spicebush swallowtail are native spicebush (Lindera benzoin) and sassafras (Sassafras albidum). When native plants are displaced by bush honeysuckle invasion, this eliminates essential habitat for the insects that rely upon these native plants. The chemical composition of bush honeysuckle leaf-litter is different than native vegetation, which alters water chemistry and impacts native insect populations in streams (13). These changes in water chemistry also influence tadpole survival and lead to reduced amphibian diversity in honeysuckle infested habitats (14).

What about the birds?: Birds, especially American Robins, consume the fruits of bush honeysuckle and are the primary means of dispersal for perpetuating its invasion (15). However, don’t get the impression that bush honeysuckle is good for birds. Honeysuckle berries provide poor quality nutrition; they are high in sugary carbohydrates and low in desirable fats compared to many of the native plants displaced by their invasion (16). Furthermore, native songbird nests in bush honeysuckle experience higher nest predation and lower fledgling survival compared to nests in native shrubs (17, 18)

Human Health: A recent study by researchers at Washington University in Saint Louis found that bush honeysuckle infestation increases human exposure to Lyme disease and Ehrlichiosis (a tick-borne bacterial infection) by increasing the activity of the tick host, white-tailed deer (19). Another recent study from the University of Illinois found that the displacement of native shrubs by invasive bush honeysuckle altered water chemistry, which caused an increase in survival and abundance of the common house mosquito, the vector for West Nile Virus (20). Lastly, the berries of bush honeysuckle are reported to be mildly poisonous to humans (21).

Recreation:  Dense infestations of bush honeysuckle on public and private lands prevent the enjoyment of our woodlands and stream banks for hiking, cycling, horseback riding, birding, hunting and other outdoor recreation. These infestations form impenetrable thickets in the understory of once open native forests and grasslands, encroaching upon trails, and limiting visibility into the surrounding environment.

Habitat management for white-tail deer and other wildlife is an important consideration for many rural landowners and hunters. There is often confusion regarding the value of invasive bush honeysuckle for deer habitat. There is an unrelated shrub in the eastern and northern US has the common name Northern Bush Honeysuckle (Diervilla lonicera), which is one of the most important plants for deer forage in the regions where it occurs. Unlike the native shrub, which does not occur in Missouri, invasive bush honeysuckle is not a quality forage plant for whitetail deer. Although invasive bush honeysuckle can provide cover for deer, if low-density patches aren’t eradicated they will rapidly develop into impenetrable thickets that creates intolerable conditions for hunting. 

Description of Bush Honeysuckle

By far the most common species of bush honeysuckle in the Saint Louis region is Amur honeysuckle (Lonicera maackii), though there are several similar invasive Asian bush honeysuckle species present in Missouri and Illinois. All of these invasive Asian bush honeysuckles are dense, upright, deciduous shrubs with shallow roots, growing from 3-15 feet in height, with opposite leaves and pairs of brightly colored red or orange berries near the base of the leaves in fall.

Amur honeysuckle (often referred to simply as bush honeysuckle; Lonicera maackii) is the most common species in our region, and has pale yellowish-white flowers and bright red, nearly translucent berries.

Bell’s honeysuckle, or fly honeysuckle, (L. x bella) is also invasive in Missouri and Illinois. Morrow’s honeysuckle (L. morrowii) and Tatarian honeysuckle (L. tartarica) have invaded Illinois and other Midwestern states, and should be considered a threat in Missouri. This educational brochure from the Forest Invasive Plants Resource Center includes a table that compares these different Asian bush honeysuckles. This information may be of interest for the botanically inclined, though volunteers working to remove bush honeysuckle need not worry about these subtle distinctions. All of these species are invasive and are more similar to one another than to any native plant with which they might be confused.

Invasive bush honeysuckles are most easily identified in the early spring, when they leaf-out earlier than native shrubs, or the fall, when they are still green after native shrubs have dropped their leaves.

Plants Not to Confuse with Bush Honeysuckle

One of the most important steps for the control of any invasive plant is learning to correctly identify the culprit and distinguish it from plants with similar characteristics. Although bush honeysuckle is actually very distinct, the untrained eye could potentially confuse it with other shrubs that have opposite leaves or red fruits. If you’re uncertain, seek the advice of someone experienced with plant identification. Volunteering to remove honeysuckle is a great opportunity to hone your identification skills. After a few hours removing bush honeysuckle, you won’t soon forget what it looks like! Remember that bush honeysuckle holds its leaves in the fall much longer than any of the native shrubs described below. With a little experience, you’ll soon find that bush honeysuckle is unmistakable.

Japanese Honeysuckle (Lonicera japonica): [QGL1] One of the plants with which bush honeysuckle is most often contrasted is Japanese honeysuckle, a fragrant vine that is extremely common on fence rows throughout our region. Many people have fond childhood memories of eating the sweet nectar from the base of its attractive white and yellow flowers. Japanese honeysuckle can easily be distinguished from bush honeysuckle, since the former is a vine and the latter is a bush. Unfortunately, this sweet-smelling vine is also highly invasive and damaging to our natural areas! See this invasive species fact sheet from the Missouri Department of Conservation to learn more about control of Japanese honeysuckle, which is sometimes sold in nurseries as Hall’s Honeysuckle. Please remove this plant from your garden and encourage your local nursery not to sell this highly invasive species.

Native Honeysuckles (Lonicera spp.): Unlike the Asian bush honeysuckles, our native honeysuckles in Missouri (members of the genus Lonicera) are all vines. There are three native vining honeysuckles in Missouri (grape honeysuckle (L. reticulata), yellow honeysuckle (L. flava), red honeysuckle (L. dioica) and the cultivated coral honeysuckle (L. sempervirens), which is native to the Southeastern US and occasionally naturalizes in the Saint Louis region. These North American honeysuckle vines are easily distinguished from the invasive Japanese honeysuckle vine. The native honeysuckle vines have larger and thicker leaves and orange or red berries, whereas the leaves of Japanese honeysuckle are smaller and thin and the berries are black.  

Coralberry, buckbrush (Symphoricarpos orbiculatus): Coralberry, also known as buckbrush, is the native shrub most likely to be confused with bush honeysuckle. Coralberry has similar opposite leaves with entire margins, but the leaves are generally smaller compared to bush honeysuckle. The berries of coralberry are dark purple or pinkish, unlike the red berries of bush honeysuckle. Lastly, only the young plants of bush honeysuckle could cause confusion, since coralberry is only 2-4 feet tall. Bush honeysuckle can grow to be 15 feet or more.

American beautyberry (Callicarpa americana): American beautyberry is a native shrub that is popular for native landscaping. It has opposite leaves, but its purple berries form in dense clusters encircling the base of the leaves as opposed to the bright red berries that form in pairs at the leaf bases of bush honeysuckle. American beautyberry only reaches 3-6 feet in height, whereas bush honeysuckle can grow to be 15 feet or more.

Eastern Wahoo (Euonymus atropurpureus): Eastern Wahoo is a small tree or shrub up to 25 feet tall that, like bush honeysuckle, has opposite leaves and bright red berries. However, unlike bush honeysuckle, the stems of wahoo are green and flexible, and sometimes square in cross-section. The berries of Wahoo hang down beneath the leaves on long branching stalks, whereas bush honeysuckle berries are located in pairs against the base of the leaves.

Native dogwoods (Cornus spp.): Flowering dogwood (Cornus florida) is a beautiful native tree for landscaping and is the state tree of Missouri. Although it has opposite leaves and red berries, it is unlikely to be mistaken for bush honeysuckle given that it is a tree rather than a shrub. However, most of our native dogwoods (members of the genus Cornus) are shrubs, including roughleaf dogwood (C. drummondii), silky dogwood (C. amomum), gray dogwood (C. racemosa), and stiff dogwood (C. foemina). These native shrubs do have opposite leaves and can sometimes form dense thickets, but that’s where the similarities end. These native dogwood shrubs form white flowers in dense flat-topped clusters and have fruits that are either white or blue, but not bright red like those of bush honeysuckle.

Possumhaw, Deciduous holly (Ilex decidua): Possumhaw is a small, deciduous tree or shrub, 15-30 feet tall, with pale gray, twiggy, horizontal branches. Possumhaw is conspicuous in winter, with many red fruits along its slender gray twigs. The abundant red fruits could potentially lead one to confuse possumhaw for bush honeysuckle. The leaves of possumhaw are alternate and the fruits are solitary or appear to be in crowded clusters along the branches, as opposed to the alternate leaves and distinctly symmetrical, paired fruits of bush honeysuckle.  

Winterberry (Ilex verticillata): Winterberry is a small native shrub that produces showy red fruits, and several cultivars have become popular for landscaping. Like its relative possumhaw, the abundant red fruits could potentially lead one to confuse winterberry for bush honeysuckle. The leaves of winterberry are alternate and the fruits are solitary or appear to be in crowded clusters along the branches, as opposed to the alternate leaves and distinctly symmetrical, paired fruits of bush honeysuckle. 

Native Viburnums (Viburnum spp.): Blackhaw viburnum (Viburnum prunifolium) and rusty blackhaw viburnum (V. rufidulum) are attractive native shrubs or small trees with opposite leaves. However, these native Viburnums form white flowers in dense flat-topped clusters and have fruits that are bluish purple, but not bright red like those of bush honeysuckle.

 
Bush Honeysuckle Removal and Control

When: Bush honeysuckle can be removed any time of the year. However, early spring and late fall are ideal for locating and removing this invasive shrub, since it has leaves when our native shrubs and trees do not. Once you develop an eye for the yellowish-green leaves of bush honeysuckle in late fall, this time of the year is ideal for detecting isolated shrubs and removing them before the infestation expands.

How: There are multiple effective methods of removing bush honeysuckle. Selecting the right approach depends upon a number of factors, such as the area covered by the invasion, the size of the plants to be removed, and your personal capabilities and preferences. These instructions are intended to provide homeowners and volunteers information necessary to take action against bush honeysuckle. Some additional methods for controlling large-scale infestations used by professional contractors and conservation organizations with highly specialized equipment and experience are not addressed.

Hand Pull

Bush honeysuckle has a shallow root system, so seedlings and small plants can usually be removed easily by hand pulling, especially when soil is moist. However, looks can be deceiving. Plants that have been previously mowed and re-sprouted can appear small, but have large root systems. Even small plants can be difficult to pull if their roots are intertwined with other trees and shrubs. Don’t overdo it – overly ambitious pulling of larger honeysuckle bushes has resulted in serious back injury. 

Dig

Even large honeysuckle bushes can be removed by digging with shovels, pick axes, and other tools, but this is very labor intensive and causes extensive soil disturbance. Digging is a suitable approach for someone who wants to remove bush honeysuckle from their garden and replace it by planting non-invasive alternatives. It is not necessary to remove every piece of the root; bush honeysuckle will not resprout so long as the dense roots around the base of the stem are removed. However, digging is impractical for larger invasions on private lands, parks, and conservation areas. Aside from the physical challenge and inefficiency, widespread digging causes extensive soil disturbance and can damage other desirable plants. Soil disturbance creates optimal conditions for the establishment of bush honeysuckle and other invasive species, and should be avoided in streambanks or other areas prone to erosion.  

Cut Stem Application*

The most effective and efficient method of removing larger bush honeysuckle plants is to cut the stem as close to the ground as possible and immediately apply an appropriate herbicide after cutting. Don’t cut stems too fast and loose track of them before treating them with herbicide. Any stems that are cut without herbicide treatment will vigorously resprout, so it is important to treat stems promptly after cutting. When doing cut-stem treatments, safety precautions must be taken for both cutting and the herbicide treatment. Always follow the herbicide label and use required personal protective equipment. It may be intuitive that non-chemical removal methods such as digging are less harmful to the environment than any approach that incorporates herbicides. However, digging up large bush honeysuckle plants in natural areas causes extensive soil disturbance, which can damage non-target plants, increase erosion, and create optimal conditions for recolonization by bush honeysuckle and other invasive plants. The methods suggested below describe the very precise application of herbicides with low environmental persistence and toxicity, resulting in the effective control of bush honeysuckle without soil disturbance or damage to non-target vegetation. 

Cutting Tools: The best tool for cutting bush honeysuckle depends upon the size of the plants being cut and the size of the area being treated. Appropriate tools range from hand pruners, lopping shears, and folding saws to chainsaws and brush blades. Only use tools with which you are comfortable and experienced, and always use personal protective equipment.

Herbicide Type: The most frequently recommended herbicide for controlling bush honeysuckle with cut-stem application is glyphosate, because it is effective and has low environmental persistence and toxicity compared to other herbicides (22). Although the herbicide product Tordon RTU is also highly effective for cut-stem application control of honeysuckle (23), one its active ingredients, picloram, persists in the environment and can harm non-target terrestrial and aquatic plants.

Glyphosate is the active ingredient in many common broad-spectrum herbicide products. Although the chemical glyphosate itself has low toxicity, some surfactants (chemicals that increase herbicide adhesion to leaf surfaces) added to glyphosate herbicide products are highly toxic to aquatic organisms (24). For this reason, it is important that only glyphosate formulations approved for aquatic use are used near water (e.g. Rodeo, AquaMaster, AquaPro, and others).

Herbicide Concentration: An herbicide solution containing approximately 20% active ingredient of glyphosate is recommended for cut-stem application control of bush honeysuckle. Mixing a small amount of spray indicator dye (either blue or red) into the solution is helpful for keeping track of which cut-stems have been treated.

The herbicide glyphosate is the active ingredient in a vast array of herbicide products, ranging from ready-to-use foliar spray formulations that contain only 2% glyphosate to concentrates containing 50% glyphosate. The most widely available concentrates usually contain 41% active ingredient of glyphosate. Although label instructions recommend applying concentrates undiluted for cut stem application, studies have shown that a 20% active ingredient solution (1 part concentrate mixed with one part water) is highly effective for controlling bush honeysuckle (25, 26). Although mixing a 20% active ingredient solution of glyphosate from concentrate is recommended, Roundup Concentrate Poison Ivy Plus Tough Brush Killer (18% glyphosate and 2% triclopyr salt) is a ready-to-use herbicide product that is also effective for cut-stem control of bush honeysuckle.    

Herbicide Application Methods: Herbicide is only applied to the outer edge of the cut-surface, the cambium, which contains the plants vascular tissue (for an illustration, see figure A in from this informational brochure).

Various tools are often used for cut-stem application, such as spray bottles and paint brushes, which can be somewhat messy. However, one of the easiest methods for cut-stem herbicide application is a Nalgene drop- dispensing bottle, which very precisely applies herbicide directly to cut stems and won’t leak even when turned upside down. Such precision and cleanliness assures that herbicide is not accidentally applied to non-target vegetation, and also prevents accidental herbicide contact for the person treating cut stems. Small 2 ounce bottles are available locally at REI. Depending on the pace of work and the number of plants to be treated, a 2 ounce bottle may be adequate. However, a bigger bottle is more appropriate for extensive work, and 8 ounce bottles can be purchased online. If the tip of the dispensing bottle gets clogged with fine debris, it can be cleaned with warm water. Clogs can also be cleared in the field by poking the interior of the dispensing aperture with a safety pin, but this will unavoidably widen the aperture. Using a drop dispending bottle with a widened aperture is still very precise and allows for a faster flow rate, which some users prefer, but the bottle will no longer be leak-proof if it is turned upside down without the cap in place. Wrapping a strip of neon orange duct tape around the dispensing bottle is helpful to avoid losing sight of the bottle in leaf litter. 

* A Note About Herbicides: The judicious use of herbicides is often the most effective means of controlling invasive species, but careless or uneducated herbicide use can result in collateral damage to non-target vegetation and other ecological harm. Although the Missouri Botanical Garden does not explicitly endorse the use of any herbicide product, it is important that homeowners who chose to use herbicides understand correct application practices. Always follow the herbicide label and use required personal protective equipment.

Foliar Spray*

Foliar application of an herbicide solution containing 2% active ingredient of glyphosate is effective, but should only be used in early spring or late fall before or after most native plants are green. Foliar spray of any herbicide should be used with great caution and only when winds are very mild, since inexperienced applicators greatly underestimate the potential for herbicide drift to harm non-target vegetation. In diverse woodlands, foliar spray is less desirable than cut-stem application, since some native plants are still green even at the optimal times for treating honeysuckle. Foliar spray can be useful for follow-up spot treatment of any stems that resprout or were overlooked during cut-stem treatment.
 

* A Note About Herbicides: The judicious use of herbicides is often the most effective means of controlling invasive species, but careless or uneducated herbicide use can result in collateral damage to non-target vegetation and other ecological harm. Although the Missouri Botanical Garden does not explicitly endorse the use of any herbicide product, it is important that homeowners who chose to use herbicides understand correct application practices. Always follow the herbicide label and use required personal protective equipment.

Revisit/Follow Up

Revisit later in the growing season or the following season to find any plants that were missed, re-sprouted, or recently established. The leaves of small resprouts can be carefully treated using the foliar spray method described above.

Resources

Get Involved - Local Opportunities to Take Action

BiodiverseCity St. Louis is a growing network of organizations and individuals throughout the greater St. Louis region who share a stake in improving quality of life through actions that welcome nature into our urban, suburban and rural communities. The BiodiversCity website contains frequently updated information on current events and volunteer opportunities, many of which are related to invasive species control.

Operation Wild Lands (OWLS) is a community-based partnership coordinated by the Open Space Council that prepares citizen volunteers of all ages to restore and maintain public lands throughout the St. Louis region.  The Open Space Council coordinates many volunteer opportunities related to invasive species control.

Bring Conservation Home is a program of the St. Louis Audubon Society that provides advice for landscaping with native plant species, the removal of invasive plant species, water conservation on the urban landscape, and other stewardship practices that promote healthy habitat for birds, native wildlife and people.

Look for classes and workshops for working with native plants as an alternative to invasives:

 

Landscaping Alternatives to Honeysuckle

There are numerous beautiful native and non-invasive alternatives for bush honeysuckle in your landscape. Although non-invasive exotics do not actively harm our environment, they also don’t provide the same benefits as native plants for butterflies, pollinators, and the numerous insects on which birds depend for their diet. Below are some resources for alternatives to bush honeysuckle, but the possibilities are endless. To learn more about landscaping with native plants, visit the Whitmire Wildflower Garden at Shaw Nature Reserve, participate in a Native Plant School event, or schedule a home visit with an expert through the Bring Conservation Home program of the Saint Louis Audubon Society.

This Visual Guide developed by the Missouri Botanical Garden’s Kemper Center of Home Gardening provides information on several native alternatives to bush honeysuckle.

Curse of the Bush Honeysuckles: This booklet from the Missouri Department of Conservation provides suggestions for native shrubs that provide attractive and environmentally friendly alternatives in the landscape.

This brochure from the Midwest Invasive Plant Network provides useful suggestions for non-invasive alternatives to some of the worst invasive species in the Midwest, including bush honeysuckle.

GrowNative! works to increase awareness of native plants and their effective use in urban, suburban, and rural developed landscapes. Visit their website to learn about landscaping with native plants.

Look for classes and workshops for working with native plants as an alternative to invasives:

Additional Bush Honeysuckle Resources

Native Alternatives to Bush Honeysuckle and other Invasive Shrubs: A Visual Guide developed by MBG’s Kemper Center for Home Gardening.

Bush Honeysuckles Invasive Species Fact Sheet: A concise fact sheet from the Missouri Department of Conservation. 

Curse of the Bush Honeysuckles: This booklet from the Missouri Department of Conservation provides information for the identification and control bush honeysuckles, in addition to suggestions for native shrubs that provide attractive and environmentally friendly alternatives in the landscape.

Stop Honeysuckle.org: A Magnificent Missouri campaign to halt the spread of bush honeysuckle

Bush Honeysuckle Literature Cited

(1) Luken, J. O., and J. W. Thieret. 1996. Amur honeysuckle, Its fall from grace: Lessons from the introduction and spread of a shrub species may guide future plant introductions. BioScience 46:18-24.

(2) Collier, M. H., J. L. Vankat, and M. R. Hughes. 2002. Diminished plant richness and abundance below Lonicera maackii, an invasive shrub. The American Midland Naturalist 147:60-71.

(3) Hartman, K. M., and B. C. McCarthy. 2008. Changes in forest structure and species composition following invasion by a non-indigenous shrub, Amur honeysuckle (Lonicera maackii). The Journal of the Torrey Botanical Society 135:245-259.

(4) Miller, K. E., and D. L. Gorchov. 2004. The invasive shrub, Lonicera maackii, reduces growth and fecundity of perennial forest herbs. Oecologia 139:359-375.

(5) Gorchov, D., and D. Trisel. 2003. Competitive effects of the invasive shrub, Lonicera maackii (Rupr.) Herder (Caprifoliaceae), on the growth and survival of native tree seedlings. Plant Ecology 166:13-24.

(6) Boyce, R. L. 2009. Invasive Shrubs and Forest Tree Regeneration. Journal of Sustainable Forestry 28:152-217.

(7) Hartman, K. M., and B. C. McCarthy. 2007. A dendro-ecological study of forest overstory productivity following the invasion of the non-indigenous shrub Lonicera maackii. Applied Vegetation Science 10:3-14.

(8) Missouri Department of Conservation. Missouri Forest Facts. (http://mdc.mo.gov/about-us/department-details/missouri-forest-facts). Accessed online, February 2, 2016.

(9) Dorning, M., and D. Cipollini. 2006. Leaf and root extracts of the invasive shrub, Lonicera maackii, inhibit seed germination of three herbs with no autotoxic effects. Plant Ecology 184:287-296.

(10) Cipollini, D., R. Stevenson, S. Enright, A. Eyles, and P. Bonello. 2008. Phenolic Metabolites in Leaves of the Invasive Shrub, Lonicera maackii, and Their Potential Phytotoxic and Anti-Herbivore Effects. Journal of Chemical Ecology 34:144-152.

(11) McEwan, R. W., L. G. Arthur-Paratley, L. K. Rieske, and M. A. Arthur. 2010. A multi-assay comparison of seed germination inhibition by Lonicera maackii and co-occurring native shrubs. Flora - Morphology, Distribution, Functional Ecology of Plants 205:475-483.

(12) Bauer, J., S. Shannon, R. Stoops, and H. Reynolds. 2012. Context dependency of the allelopathic effects of Lonicera maackii on seed germination. Plant Ecology 213:1907-1916.

(13) Fargen, C., S. M. Emery, and M. M. Carreiro. 2015. Influence of Lonicera maackii Invasion on Leaf Litter Decomposition and Macroinvertebrate Communities in an Urban Stream. Natural Areas Journal 35:392-403.

(14) Watling, J. I., C. R. Hickman, and J. L. Orrock. 2011. Invasive shrub alters native forest amphibian communities. Biological Conservation 144:2597-2601.

(15) Bartuszevige, A., and D. Gorchov. 2006. Avian Seed Dispersal of an Invasive Shrub. Biological Invasions 8:1013-1022.

(16) Smith, S. B., S. A. DeSando, and T. Pagano. 2013. The Value of Native and Invasive Fruit-Bearing Shrubs for Migrating Songbirds. Northeastern Naturalist 20:171-184.

(17) Schmidt, K. A., and C. J. Whelan. 1999. Effects of Exotic Lonicera and Rhamnus on Songbird Nest Predation. Conservation Biology 13:1502-1506.

(18) Rodewald, A., D. Shustack, and L. Hitchcock. 2010. Exotic shrubs as ephemeral ecological traps for nesting birds. Biological Invasions 12:33-39.

(19) Allan, B. F., H. P. Dutra, L. S. Goessling, K. Barnett, J. M. Chase, R. J. Marquis, G. Pang, G. A. Storch, R. E. Thach, and J. L. Orrock. 2010. Invasive honeysuckle eradication reduces tick-borne disease risk by altering host dynamics. Proceedings of the National Academy of Sciences 107:18523-18527.

(20) Gardner, A. M., B. F. Allan, L. A. Frisbie, and E. J. Muturi. 2015. Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae). Parasite Vectors 8:329.

(21) US Forest Service. Amur Honeysuckle. (http://www.na.fs.fed.us/fhp/invasive_plants/weeds/amur-honeysuckle.pdf) Accessed online, February 2, 2016.

(22) Hartman, K. M., and B. C. McCarthy. 2004. Restoration of a Forest Understory After the Removal of an Invasive Shrub, Amur Honeysuckle (Lonicera maackii). Restoration Ecology 12:154-165.

(23) Rathfon, R., and K. Ruble. 2007. Herbicide treatments for controlling invasive bush honeysuckle in a mature hardwood forest in West-Central Indiana. Tech. Rep. SRS–101. U.S. Department of Agriculture, Forest Service, Southern Research Station: 187-197.

(24) Langeland, K. A., and L. A. Gettys. 2006. Safe Use of Glyphosate-Containing Products in Aquatic and Upland Natural Areas. Tech. Rep. SS-AGR-104. Center for Aquatic and Invasive Plants, University of Florida. IFAS Extension.

(25) Kline, V. 1981. Control of honeysuckle and buckthorn in oak forests. Restoration and Management Notes 1:18.

(26) Schulz, K. E., J. Wright, and S. Ashbaker. 2012. Comparison of Invasive Shrub Honeysuckle Eradication Tactics for Amateurs: Stump Treatment versus Regrowth Spraying of Lonicera maackii. Restoration Ecology 20:788-793.