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Amur Honeysuckle: Why We Care

Many CEES service learning events are centered around the removal of invasive species. One species we remove particularly often is Amur Honeysuckle (Lonicera maackii). Since 2010, CEES has facilitated service learning events for over 880 IUPUI students specifically to remove Amur Honeysuckle, totaling over 3800 hours of environmental restoration service.  

Honeysuckle was intentionally brought to the United States from Asia and cultivated as an ornamental plant.  Since its introduction, honeysuckle has proliferated across east-central US.  Once it establishes itself in an area, honeysuckle takes over in a voracious manner, creating near monocultures; it has also been shown to reduce the growth and fecundity of native plant species, giving it a distinct competitive advantage.  

In Indiana, Amur Honeysuckle is particularly invasive in central and northern parts of the state, but it is starting to move into the southern portion (Source).  Amur Honeysuckle thrives in edge or disturbed habitats like riparian zones near bodies of water and lining our roadways. Chances are, you drive past Amur Honeysuckle every day!  


Current distirbution of the invasive Amur Honeysuckle

Current distribution of the invasive Amur Honeysuckle in North America. (Source: USDA)

This past Monday, Jan 26th, Dr. Ryan McEwan, Associate Professor of Ecology at the University of Dayton, visited IUPUI to present on the terrestrial and aquatic impacts of Amur Honeysuckle.  During his talk, Dr. McEwan spoke on the "novel weapons" that honeysuckle posses which give it a competitive advantage over native plant species.  Below is a brief summation of his findings and links to original publications on the topic.












  • Honeysuckle has a unique leaf phenology; it leafs out earlier and retains its leaves longer than its native counterparts (Citation)
  • Honeysuckle exudate inhibits seed germination, giving it allelopathic effects (Citation)
  • Honeysuckle limits the amount of throughfall rain through the canopy (Citation)
  • Honeysuckle throughfall has a cation concentration up to 3 times greater than normal throughfall (Citation)
  • Honeysuckle leaves decompose more than 5 times faster than native leaves in terrestrial environments (Citation)
  • Honeysuckle has a distinct microbial community that colonizes its leaf litter (Citation)
  • Honeysuckle does not experience herbivory like its native counterparts (Citation)
  • Honeysuckle leaves decompose 4-5 times faster than native leaves in aquatic environments (Citation
  • Honeysuckle alters the macroinvertebrate species makeup of aquatic environments (Citation)


  • Phenology: the study of periodic animal and plant life cycles and how they are impacted by seasonal variations
  • Allelopathic: a biological phenomenon by which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms  
  • Throughfall: the process which describes how wet leaves shed excess water onto the ground surface
  • Herbivory: the process whereby an organims eats a plant or plant-like organism 

FOR MORE INFORMATION check out our links to web resources here.  Dr. McEwan also suggested looking into the work of Dr. Don Cipollini at Wright State University for more information on the allelopathic effects of Amur Honeysuckle.

Honeysuckle retains its leaves in the fall, long after its native counterparts have dropped theirs.

It's also possible to view Amur Honeysuckle via satellite.  Learn more about this in the video below.

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