Invasive Species Task Force

What Is It?

The Invasive Species Removal Task Force for Ouabache Trails started in late fall of 2012 through the concern of a few volunteers who began the control effort.  There are several invasive species invading the park, but, by far, the worst is Euonymus fortunei, also known as Winter Creeper (see below).  Because of the abundance and negative effect of this species, the Task Force is focusing on the removal of it before other species.

E. fortunei is, literally, taking over the park. A walk down Trail 1 (which starts near the park office), or onto the trail connecting Fort Knox II State Historic Site with Trail 1, or many other trails, shows abundant evidence of this plant, which is carpeting the ground and growing up tree trunks. It is fast-growing and aggressive.  It is also evergreen, so it is very easy to see in fall and winter.  In the spring, it shades the ground, blocking sunlight from native wildflowers and ferns, and competing for nutrients and moisture. Ouabache Trails is a very botanically rich area, especially during spring wildflower season.  This special quality is immediately threatened by E. fortunei.  After the vines grow up a tree (rootlets hold fast to the trunk all along both sides of the vine), it flowers and produces fruit.  The fruit is a white capsule that opens to reveal three bright crimson, teardrop-shaped berries.  These berries are dispersed by falling to the ground, but also by being eaten and dropped by birds and other animals.  It is most important to control the E. fortunei vines on the trees to prevent seed dispersal. E. fortunei is ranked HIGH on the Official Indiana Invasive Species Council Invasive Plant List:

More information about E.fortunei can be found here:

Besides vine-covered trees, we have also been working on some rock faces that extend over the large creek.  Some of these have had many vines cascading over the edge and reaching down to the creek.  Our first project was a large and particularly dense overhang, which is now completely clear of E. fortunei (including a vine-covered tree on top of the cliff). We hope to soon post before and after photos of this project, showing what just two people can accomplish.

Anyone interested in joining the Task Force to help control this invasive plant, and others, is welcome.  More information can be found below under “Being a Part”.

Control Methods for E. fortunei/Winter Creeper

The Invasive Species Removal Task Force for Ouabache Trails is constantly searching for information and learning more about methods of removal and control.  First, we focus on vine-covered trees, particularly those vines producing fruit.  We use tools to dig out roots of thinner vines immediately below a tree, carefully removing the vine, its roots and rootlets.  Some of these vines are very long and can form a network extending across the forest floor, or up a tree.  There are also older, thick, woody vines on the trees.  We carefully cut out a section of the woody vine not far from the bottom of the tree, using a hand saw.  From the cut and all the way up, the vine dies.  It becomes, a week or so later, easy to locate the trees thus treated, by the dead and dry Winter Creeper leaves.

The lower cut needs to be treated to kill off the rest of the vine that enters the ground.  A cut to a vine that is not killed will make the vine grow even more aggressively, so it must be treated to stop it.  We are currently researching methods for this, and experimenting.  We are trying to find out if, when a lower cut on a woody vine is poisoned, it also kills off the whole network of vines connected with that.  Care must be taken to treat a plant correctly – not all types of plants respond to the same methods in the same way.

We are also researching the correct treatment of E. fortunei leaves to kill off networks of vines, including the best time to do so. Foliar spraying can be done in the fall when native plants are dormant, and before temperature reaches below the levels at which treatment is effective.

Special care is taken to pack up all removed vines, vine segments, stemmed leaves, roots, and fruit from the work site.  All material is packed tightly into large plastic bags that are provided by the Knox County Parks Department, then taken to the Maintenance building at Ouabache Trails.  The staff eventually burns the material.  This material cannot be dumped anywhere, as the vines will re-root and become a problem elsewhere.

In the clearing process, we are very careful not to disturb other things such as native plants, mosses, tree bark, animals, etc.

Why Be a Part of the Task Force?

  • You will be doing something vitally important for the environment and for beautiful Ouabache Trails Park.  The effects of what we do at the park reach well beyond its borders.  And the immediate effects are visible.
  • You will be enjoying Nature all around you.  We are aware of birds, other animals, plants, fungi, insects, and the whole natural environment.
  • It is healthy:  fresh air, sunshine, and great exercise!
  • Though we work hard, we also have a lot of fun.  There is conversation, camaraderie, and those funny “Laurel and Hardy moments”.
  • There is a great sense of accomplishment and satisfaction with each removal or control. The problem looks overwhelming when you see the extent of it. But, seeing what just a couple of people have accomplished brings great hope for what many more can accomplish.  Each time we save a tree, and each time we clear a rock face, we experience deep satisfaction and accomplishment.  “Many hands make light work”.
  • You will make new friends.

Being a Part

Anyone interested in helping to control invasive plants at Ouabache Trails Park is welcome.  All that is required is your interest and fortitude, but there are suggestions below for what to bring.  We do ask that you read “Things to Know” and follow the methods of control, and that you understand you are working at your own risk.

We have been meeting for work on Wednesday mornings at 8:00 a.m. Eastern time.  You can meet us at that time or anytime after (we often work up to lunchtime, but sometimes it is just for a couple of hours.)  You only need to show up.  We also hope to have an all-day Saturday workday this winter.  We will discontinue the pulling of E. fortunei in the early spring when spring ephemerals (woodland wildflowers) start coming up, so as not to disturb them.  However, in spring and summer we can continue to cut thick vines growing up trees (and treat the lower cut) so that we can decrease the number of berries occurring in late fall.

To keep up on information and find out dates and times we are working, as well as where in the park we are working:

Things to Know

  • You WILL get dirty!  Come prepared.
  • Sometimes it’s very cold, but we warm up quickly. Come prepared.
  • Please be very careful not to disturb native plants, mosses, lichens, fungi, liverworts, insects, other animals, etc.  If you do disturb the root or corm of a native plant, for example, please gently replace it.
  • Please be careful not to harm tree bark, as this can allow infection and other problems to enter the tree.  Be careful when removing vines and when cutting into a woody E. fortunei vine.
  • Be sure to remove all roots and rootlets.  They will reproduce if left behind.
  • Be sure to gather up all material for disposal:  stemmed leaves, vines, roots, pieces of stem or vine, and berries.  Every little thing can grow more E. fortunei!  Everything goes into a large plastic bag for proper disposal.
  • Use prying tools to try to completely lift a vine or remove roots.
  • Work at your own risk, but please also take every precaution for the safety of yourself and others.
  • Learn to identify Poison Ivy vines, particularly the way they look in winter, to avoid problems to yourself.  It is also good to learn to distinguish between the vines of Winter Creeper (Euonymus fortunei), Virginia Creeper (Parthenocissus quinquefolia), native grapes (Vitis spp), and Poison Ivy(Toxicodendron radicans) to make sure you are pulling the correct vines. Information will be provided soon on these comparisons.  Until then, check sources of information for shrubs and woody vines in Indiana or the Midwest.
  • Have fun!

What to Bring:

  •  Just bringing yourself and your own willingness to work is enough (though bringing a friend or more is good, too.)  But, below are suggestions on some things you can bring, if you have them:
  •  Work gloves  (especially warm ones for those really cold mornings)
  • Hand warmers are helpful (those little packets that heat up when you squeeze them – great in gloves or pocket). We do find that our hands warm up when we get working.
  • Wet boots, if we are working around a creek or wetland
  • Time piece (i.e. a watch).  If you’ve been to Ouabache Trails often enough with a cell phone, you know that the time shown on your phone switches around between Indiana and Illinois time as you move to various locations.  This can happen just from walking from one spot to another, or going up a hill.  So, if you want to really know what time it is, a watch is good.
  • Camera (it’s fun to document all of this)
  • drinking water
  • a snack
  • a lunch, if you are working long enough
  • tarp (we lay tarps below the work area to catch vines, pieces and berries)
  • those large collapsible yard-and-garden buckets are great – they hold up a large trash bag and make it much easier to drop material into the bags.
  • wheelbarrow or cart (very good for transporting tools and such to the work site)
  • various tools.  Helpful ones are:  pruning saws (small ones as well as long-handled), “dandelion diggers” or other tools for digging weeds (we’ve found this to be one of our most-used tools), clippers, loppers, tools for prying, hand hoes, and any long-handled tools you might have that can be used for reaching up and pulling down vines.

Hope to see you there!

 Note: Other invasive plants at the park to be considered for control are:  Burning Bush (Euonymus alatus), Bush Honeysuckles (Lonicera spp.) and Multiflora Rose (Rosa multiflora). Others may be added, if found and identified.

We are grateful for the help and support of this project by Rama Sobhani (Superintendent of the Knox County Parks and Recreation Department), park department staff, and the Executive Board of KCPRD.