Plant Native, Not Invasive
What is an invasive Plant?
The U.S. government defines an invasive species as one “that is not native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” For example, all nine species of privet are invasive species because they are native to Asia and Africa; reproduce both sexually and asexually; quickly colonize in a disturbed area (reducing biodiversity); mature quickly; and outcompete native shrubs and trees.
An invasive plant can be harmful in various ways, such as:
- Reducing or eliminating native food sources for wildlife
- Providing poor quality food for wildlife (similarly to fast food, low in nutrition but in large quantity)
- Reducing natural shelter for wildlife
- Changing the physical structure of the ecosystem affecting nutrient cycles and natural water flow
- degrading croplands and forests
Why are plants invasive?
- They spread easily by producing many seeds or spreading by roots or rhizome.
- They grow taller, faster, and wider than native species; thus displacing native plants.
- By displacing native plants, they take over as a monoculture; thus, reducing plant diversity.
- The seeds are easily moved by wildlife, wind, or water.
Are all cultivars invasive?
- No. Not all introduced or non-native plants are invasive.
- However, many invasive plants were brought to the United States intentionally. They were planted because of their beauty (e.g., orange daylilies); because they were thought to control erosion (e.g., privet); or because they were used in farming (e.g., Johnsongrass).
What Can I do to help control the spread of invasive plants?
- Do not plant invasive species. Many gardeners think that their one bush is staying put and harmless, but birds and easily spread seeds far and wide.
- Remove invasive species from your garden. Review and learn about invasive species in your state and region. If you have them in your garden, remove them. There are many great native alternatives.
- Inform your gardening friends about invasive species and why they are harmful to the ecosystem in our state.
- Encourage your local nursery or landscaper to not carry invasive plants.
Kentucky’s Least Wanted Plants
In 2013, Kentucky’s Exotic Pest Plant Council developed a list of invasive plants in Kentucky that is still useful today. The council and state experts assigned numerical values to invasive plants based on the distribution; the rate of spread; the amplitude of habitats they could invade; and threat rates in surrounding states. The list is divided into four threat levels. It is linked below. Kentucky gardeners should become familiar with the list and work to remove these plants from their gardens.
Gardeners often wonder if there are native alternative to the invasive plants, and the answer is a resounding YES! The Garden Club of Kentucky worked with the Kentucky Exotic Pest Plant Council to develop the brochure linked below to help gardeners find replacements for invasive species.
Between 2000 and 2017, Bernheim Arboretum and Research Forest, the Southeast Exotic Pest Plant Council, and the Environmental Resource Management Center at Northern Kentucky University publishes a poster of those plants that have proven to be invasive of our native habitats and possible native alternatives to the invasive plant. We have linked those posters below.
Least Wanted Plant of 2017: Japanese Barberry
Native Alternatives: Virginia Sweetspire, Arrowwood, Black Chokeberry
Least Wanted Plant of 2016: Chocolate Vine (Akebia quinata)
Native Alternatives: Trumpet Honeysuckle, Virginia Creeper, Crossvine
Least Wanted Plant of 2015: Mimosa or Silk Tree
Native Alternatives: Alternate-Leaf Dogwood, Red Buckeye, American Witch Hazel
Least Wanted Plant of 2014:Porcelain Berry
Native Alternatives: Pepper-Vine, American Wisteria, Raccoon-Grape
Least Wanted Plant of 2013: Autumn Olive & Russian Olive
Native Alternatives: Common Elderberry, Black Chokeberry, or Blackhaw Viburnum
Least Wanted Plant of 2012: Sweet Autumn Clematis
Native Alternatives: Passionflower, Dutchman’s Pipe, or Virgin’s Bower
Least Wanted Plant of 2011: Lesser Celandine
Native Alternatives: Lobed Tickseed, Celandine Poppy, or Green & Gold
Least Wanted Plant of 2010: Privet
Native Alternatives: Red Chokeberry, Ninebark, or American Holly
Least Wanted Plant of 2009: Callery Pear (Bradford Pear)
Native Alternatives: Fringetree, Rusty Blackhaw, or Wild Plum
Least Wanted Plant of 2008: Princess Tree
Native Alternatives: Yellowwood, Northern Catalpa, or Serviceberry
Least Wanted Plant of 2007: Japanese Knotweed
Native Alternatives: Buttonbush, Blue False Indigo, or Fragrant Sumac
Least Wanted Plant of 2006: Asian Bittersweet
Native Alternatives: (Red) Trumpet Honeysuckle, American Bittersweet, or Cross vine
Least Wanted Plant of 2005: Chinese Silver Grass
Native Alternatives: Switch Grass or Indian Grass
Least Wanted Plant of 2004: Burning Bush
Native Alternatives: Strawberry Bush, Spicebush, or Winterberry Holly
Least Wanted Plant of 2003: Crown Vetch
Native Alternatives: Prairie Wildflower mix
Least Wanted Plant of 2002: Wintercreeper
Native Alternatives: Ginger, Allegheny Spurge, Mountain Lover or Cliff Green
Least Wanted Plant of 2001: Purple Loosestrife
Native Alternatives: Blazing Star, Great Blue Lobelia, or Obedient Plant
Least Wanted Plant of 2000: Shrub Honeysuckles
Native Alternatives: Winterberry Holly, Spicebush, or American Cranberry Viburnum
For More Information: http://www.se-eppc.org/ky/leastwant.htm