WHAT ABOUT POISON IVY? AKA Toxicodenron radicans

When we think about plants that are invasive, it is awfully difficult not to include our native plant poison ivy.  Perhaps I am just seeking revenge in posting it on this blog.  While it is not true of many, there are a few native plants that share some of the aggressive growth characteristics that non-native invasive plants have.  Poison ivy is one of them.  It is a plant most of us despise because of the itchy painful rash (contact dermatitis) caused by coming in contact with the oily and difficult to remove urushiol contained in its foliage, stems, roots, flowers, and seeds.  All parts of the plant contain this substance.  Urushiol is present during any stage of the plant's growth.  It is also present when the plant is in dormancy, and even when the plant is dead. I have never had a summer go by without getting a horrible rash from poison ivy.  It is not that I can't identify the plant, it's more like I think maybe I can get away with it just this time by wrapping the stem with a big maple leaf and pulling it out quickly.  Having lost the battle just about every year, I have become somewhat of an expert on treatment for the rash.  If you happen to come in contact with this plant accidentally, I highly recommend using Tecnu products. In my opinion, Tecnu Poison Ivy & Oak Scrub is a miracle worker. It will wash off the oily urushiol if used shortly after contact.  It will also help to relieve itching and help to dry any rash you end up with from contact and not washing off in time. 

Have you wondered why there seems to be more poison ivy these days than in the past?  Well, this plant happens to be one of only a few native plants that are capable, like many non-native invasive plants, of taking advantage of the warmer temperatures and the higher concentration of carbon dioxide in the atmosphere.  These changes are propelling poison ivy to grow into the lush vines that festoon many of the trees along the edge of the wood line.  This new enhanced version of the plant actually produces a more virulent version of urushiol, causing an even more severe reaction for us humans. 

It is fine to eliminate poison ivy if it is growing in a place where you do not want it to be.  It is under absolutely no threat of becoming endangered.  If it is growing in a place that you can avoid contacting it, it is best to just leave it alone. This plant is a very good food source for our native wildlife.  The vine has small white flowers that native pollinators visit.  The resultant seeds that form remain on the vine most of the winter making them an available food source for birds that choose to spend their winters here with us.  Deer, black bear, raccoons and other wildlife graze on the plant's foliage with no negative effect from the urushiol.  In fact, most humans, some primates, Guinea pigs, and most bats are the few species plagued by contact dermatitis from poison ivy's coating of urushiol.  This is due to the fact that none of these mammals are capable of creating their own vitamin C.  Early primates were capable of doing so, but as they continued to evolve, and eventually evolved into homo sapiens, that ability was lost.

HOW TO REMOVE

For small infestations, hand pulling using waterproof gloves and protective clothing can be helpful.  The plant has a long trailing rhizome system with periodic clusters of roots along its length.  This eventually connects to a tap root, so it is pretty difficult to pull the whole thing.  If the plant is growing on the ground along a wood line, simply mowing it repeatedly will control it well enough. Both sheep and goats can and will eat poison ivy with no negative effects, so they can be quite helpful in controlling its spread as well.

For larger infestations, especially those that are climbing in trees, the recommended herbicides are Glyphosate or Triclopyr.  Glyphosate can be used as a foliar spray.  Spraying is best performed later in the plants growing season when flowers are forming.  Keep in mind that Glyphosate is a non-selective herbicide meaning it will kill other broad leaf plants as well as grasses.  Another method is to cut the vine and paint the cut portion with a concentrated form of glyphosate.  An herbicide containing Triclopyr is also recommended.  As with Glyphosate, you can apply it as a concentrated version to the cut vine to prevent regrowth.  If using any herbicide as a foliar spray, spray on a calm day when the plant has reached full leaf growth.  If using Triclopyr as a foliar spray avoid spraying it on the trunks of trees, especially those with smooth bark or on the bark of trees with smaller diameters, as it can be absorbed through the bark and will harm the tree.  Triclopyr will not harm grasses.  DO NOT BURN POISON IVY!  Smoke and ash from burning this plant can carry the urushiol not only to your skin, but also to your mouth, eyes, nasal passages, and lungs.  THIS CAUSES A VERY DANGEROUS REACTION!