Poison Ivy (Toxicodendron¹ radicans ssp. radicans, Toxicodendron radicans ssp. eximium or Toxicodendron rydbergii) and Poison Oak (Toxicodendron diversilobum or Toxicodendron pubescens), members of the plant family Anacardiaceae, are both climbing vines that are tough to deal with.  While every good Boy Scout is supposed to know how to identify and avoid these plants, getting rid of them seems to be a problem for many gardeners.
 

Skin Irritation

Of course, the reason these plants are so often on the "get rid of it" list is because of the irritating effect they have on skin when contacted.  These plants, along with poison sumac (Toxicodendron vernix) contain an oily resin called urushiol which, on contact, produces a sever form of dermatitis (cleverly named "poison ivy dermatitis" or more medically sounding "Rhus dermatitis").  While different people are affected differently, there is no absolute immunity to this.  Furthermore, because once exposed to urushiol, a person may become more sensitive, subsequent contact with it may result in worse and worse cases.

The rash that results from contact with urushiol can vary considerably in severity.  In extreme cases, medical attention is needed.

Once a body part has been exposed to urushiol, the rash can be spread to any other body part subsequently contacted by that body part.  Hands, exposed to the resin, can spread the oils elsewhere on the body, and thus, spread the rash.  Urushiol will also cling to clothing and a person can be affected by touching the clothes that touched the plant.  Likewise, if the oil gets on tools, it can be transferred to a person who later touches them.  Urushiol can also be carried on pets who do not break out and spread to those who pet them.

There is a possibility that the rash can be avoided if the oily resin can be washed away quickly.  When exposure to one of these plants is suspected, immediately wash with soapy water, extensively.  Because the irritating agent is an oily substance, the use of soap is necessary.  Once the oils are washed away the risk of further irritation is removed.  Only parts of the body that come in contact with urushiol will develop the rash.

Burning poison ivy (or logs covered in it) will release the chemical into the smoke.  Since smoke follows beauty, this is a clever way to make all the "pretty" people ticked off.  Anyone else in the smoke will also become affected.  I have heard that inhaling such smoke can cause internal affects. (OK, let's just say inhaling ANY smoke is bad and be done with it....)

Once the rash develops, blisters will likely form.  If the oil that caused the rash has been washed away, then further spreading of the symptoms will not be possible.  It is a myth that (after you have washed away the urushiol oil) you can spread the rash by touching yourself or others.  While contact with any person's body fluids is not advised (that sort of goes without saying) you cannot catch poison ivy from touching a person who has it.  (This comes from the mouth of the dermatologist who treated my son for the condition.  I will not name him because I do not have his permission to quote him, but I promise he said it.)

Dealing with the Plants in Your Garden

Like most vines, poison ivy and poison oak have tough root systems that fight the good fight, even if the plant is cut off.  Cutting the plants and discarding the vines can make a big difference above the ground, but the roots will live on and push up more vines.  (You can also get the rash from handling the roots -- as in when you are digging around to plant something and come across this big root and start pulling it....)  The root systems of these plants may spread considerable distances.

This is important to know, because one of the most effective means to get rid of these undesirable plants is to dig up the roots.  Make sure to wear protective clothing and especially gloves.  Dig and pull the vines and roots up.  Dispose of them in a bag (paper or plastic?) so they can be handled later safely.

For small, isolated vines, try this:  Get one of those plastic store bags and put your hand (with glove to be save) inside it.  Then, pull the vine, using the bag as a glove of sorts.  Now, with the vine in your had, turn the bag inside-out.  Now the vine is in the bag!  (This works with dog dropping too!)

Because these plants are climbers, the tend to be found around trees.  It is difficult to effectively dig them up around the trees because their roots and the tree roots can become entangled.  The only choice beside digging is poison.  There are two poisons that I have used effectively:  Roundup® (Glyphosate) and Brush-B-Gon® (Triclopyr).  Both are non-selective herbicides and will kill whatever they come in contact with.  Spray these onto the green leaves of the vine where they are absorbed.  The vine will die back and kill the root.  With larger plants, spray as much of the leaves as you can.  Multiple applications may be required.

One of the tips on the tip page of this site suggest mixing a container of poison and placing the curled vine into it.  The vine will then absorb a huge amount of poison and reduce the likelihood for the need of multiple applications.

My Poison Ivy/Oak Experience

In December of 1996, we moved into our home that we had built on a wooded lot.  One property line borders a cemetery that dates back to before the Civil War.  The fence on the border was covered in honey suckle and poison ivy/oak.  I started working on this problem in March of 1997.  Beginning then, I had some area of my arms and hands broken out with poison ivy until about July when it became too hot to do much more than cut grass and water.  I had dug out many, many vines from around the fence line.  I had applied two or three applications of poison to the plants.  Very little of the vines could be found in the yard.

By August, however, vines were popping up in some of the old locations again.  Another round of treatment with poison followed.

Then next spring (1998), some of the roots still holding on pushed up more vines.  I treated them with poison and dug some too, and by the end of the summer, most of the yard was poison ivy/oak free.

When spring of 1999 rolled around, none of the old vines came back up, but the constant battle with those creeping under the fence went on.  A couple of vines appeared in odd, never before seen places, but they were small and easily disposed of.

Dealing with these vines is difficult.  The risk of being exposed to the toxin makes it, however, a necessary task.  With persistence, however, it is a battle that can be won.
 

Notes:

¹Some systems identify the Genus as "Rhus" for these plants.

Sources:

Author, Personal experiences

Taxonomy information from Stephen Jankaliski via e-mail

Thomas, Claton L. (Ed.) 1973.  Taber's cyclopedic medical dictionary.  Philadelphia: F. A. Davis Company.

http://res.agr.ca/brd/poisivy/title.html