'Introduced' plants pack impact

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By Bryce Roberts

Most of us have heard the phrase “One man’s trash is another man’s treasure.”  You can apply this adage to your landscape just as easily as you can apply it to your attic.  It may surprise you to learn some flowers and landscape plants you find attractive are actually weeds that can have a negative economic impact on the environment. 

Plant species are considered weeds when they interfere with human activities or welfare.  Some plants are known to be potentially poisonous to animals.  Others cause skin irritations or allergic reactions in people.  A plant desirable to one individual can be a menace to another.  A good example of this is annual morning glory.  You can find morning glory in catalogs and in some nurseries as a landscape plant.  For a grain crop farmer, this flowering vine can cause significant losses in crop-yield potential.

Many plants classified as weeds are not native to the United States.  Most have been introduced through travel and trading in commerce with other parts of the world.  Here are a few weeds to watch out for when you plan your landscape project. 

Musk thistle:  Also know as Nodding thistle.  This native of Europe and Asia was first discovered in the Mammoth Cave area in the 1940s.  Today, musk thistle is widespread across Kentucky and each year farmers, landowners and roadside maintenance crews spend a significant amount of time and money to combat its growth and spread. 

Johnsongrass was introduced in the 1800s as a forage crop.  Currently, this plant is one of the top 10 problematic weeds throughout the Southeastern United States, including Kentucky.  But, it can be used as a forage crop today if we end up in a drought situation. 

Multiflora rose was originally introduced for use as a living fence and wildlife cover.  This highly invasive species now inhabits pastures, desirable landscapes and wasteland areas. Similar rapidly spreading ornamentals that have escaped from landscapes include Japanese Knotweed, Bush Honeysuckles and Star-of-Bethlehem.

Kudzu was introduced as an ornamental plant in the late 1800s.  Kudzu is a major problem in many areas of the Southeastern United States due to its aggressive nature.  It also is a host plant for Asian rust, a new disease problem in soybeans.  Considerable costs and control efforts are initiated each year to combat the runaway spread of Kudzu. 

Many of these introduced plants spread easily and aggressively from one location to the next.  They crowd out and suppress the growth of more desirable vegetation. This can alter habitats and also cause losses and a reduction in quality for crops and forages. 

You can avoid these problems with careful thought and planning. Learn the characteristics of plants you intend to add to your landscape.  Do they grow rapidly or spread easily?  Find out the origins of the plant.  Is it imported from an exotic location?      Take precautions to ensure that non-native plants do not turn out to be our next plant enemy. 

Feel free to contact me at Spencer County Cooperative Extension Service, 477-2217 or email me at broberts@uky.edu.  You can visit the Spencer County Extension Services’ website at www.spencerextension.com.

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