Questions on: Poison Ivy

Ron Smith, Horticulturist, NDSU Extension Service


Q: We have been clearing a wooded lot to build a house on next spring. We would like to know what we can safely use around the base of trees to kill the remaining poison ivy. An article I read said to use Roundup, but we donít know if there is a specific kind to use. Also, the ground where the poison ivy was growing will be worked up in order to plant grass. Do we have to worry about it growing back? Is there something we can do to make sure it doesnít? (e-mail reference)

A: Roundup, or the many formulations of Glyphosate, will control poison ivy as long as it is in leaf and the overspray doesnít hit any of the desired green vegetation. Getting it on the bark or in the soil will not be a problem because it becomes deactivated immediately. It is only effective on the foliage, where it is taken in and translocated to the roots for an effective kill. Monitor the area for the next couple of years after you have carefully removed all visible signs of the poison ivy. Birds relish the fruit, so the seed may be deposited around the site, waiting for the opportunity to germinate. A selective herbicide, such as Trimec, will effectively control any emerging seedlings or shoots from remaining root pieces.


Q: I have undeveloped lake property with well-established poison ivy. The property has been burned out, Round up applied and it comes back eventually. I am very sensitive to this plant and have avoided any serious injury. Is there any chemical that can eliminate this weed completely or can I control it with other types of ground cover? Ideally I would like to know if there is a way to completely eliminate this plant. (E-mail reference)

A: Hire a professional pest exterminator to do the job. If they cannot kill it with the chemicals they have in stock, nobody can. They can use more potent material than you can purchase and are licensed to handle such material.


Q: During a break in the winter weather, we decided to clear out our poison ivy growth while it was still dormant. Much to our surprise, every one of us came down with the classic symptoms of poison ivy contacta rash, blisters, swelling, burning, itchingyou name it! I thought that we would be safe in handling this blasted vine during the dead of winter with our clothes, gloves and boots to protect us, plus the lack of foliage. Can you tell me anything about this plant? How is it picked up during the winter? How were we able to get it essentially all over our bodies almost as if we ran naked through the plants? Any assistance would be appreciated! (Wahpeton, N.D.)

A: Another painful lesson learned the hard way! Poison ivy has a toxic oil or resin produced in all parts of the plantactively growing, dormant, or dead. I assume you didn't burn the plants, as that would have put everyone in the hospital.

The toxin gets on anything it touchesclothes, pruning shears, shovelsand it sets up in the skin within 15 minutes of making contact. I suspect that the normal caution was down because of winter conditions, and everyone made bare skin contact with the tools, gloves and boots. As for the other body parts so affected, sawdust must have worked its way to those areas. Those clothes are considered contaminated and should be washed separately with Fels Naptha soap and rinsed completely in hot water. Obviously everyone involved was quite sensitive to the plant's toxic resin. It used to be that I could handle the plant bare-handed and never suffer the consequences. I was bragging about this minor feat one day to a group of folks who happened to have a dermatologist among them. I was promptly scolded as being a foolish show-off and told that my immunity would be "used up" some day, and that I would suffer terrible symptoms. Since then, I have kept my hands very carefully to myself around any poison ivy.


Q: This past summer we purchased lake shore property on West Battle Lake, Ottertail County Minn. There was a heavy growth of brush, etc., including poison ivy and poison sumac as well as regular sumac. We cleared the brush, and have sprayed the property four times with a product containing Tryclopyr which was recommended for use on lake shore property. This has all been in an effort to kill the poison ivy and sumac. Currently we have a cabin under construction and are concerned about how to stop the future growth of the poisonous plants. I dug a trench for electric conduit in early November and evidently came in contact with poison ivy roots, as I am now going through my third medical treatment this year for poison ivy. The soil is sandy and top soil will need to be added to establish a yard. What should we do to prevent recurrence of these plants? We have small grandchildren that will be visiting frequently and are very concerned about their exposure. (Sartell, Minn.)

A: Poison ivy is nothing to take lightly. While we are all born with an initial immunity, once past that stage in our lives, it can create an almost eternally itchy rash. Iím sure you donít need to be told! There are cultural and chemical controls for Rhus radicans ( poison ivy). My advice- - stay away from any cultural control. Here is a listing of chemicals Iíve been able to run down for poison ivy control.

Glyphosate -- sold as Roundup - Apply as a 2% solution with hand-held equipment.
Crossbow -- this is a 2,4-D/triclopyr combo. This mixture will deliver a synergistic effect that neither herbicide applied separately will have.
Weedmaster -- this is a dicamba plus 2,4-D mixture that is very effective in eliminating this irritating plant.

Keep in mind that all parts of the plant are poisonous at all times, even in winter. I had a professional associate in Ohio who was clearing a wooded area in winter to build a condo complex. Much of the shrub and tree growth was cut and burned -- without realizing some of it contained poison ivy. Just from smoke drift, two of his men were hospitalized! Perhaps your best approach is to have a professional apply glyphosate. It is not soil active and is very much translocated. Keep in mind also that the fruit is very desirable to birds and other wildlife, and as the seed passes through their digestive systems, it can grow where it is dropped. You might look for a product known as Multi Shield that can be applied prior to possible exposure to this plant. And of course, there is nothing like educating your grandchildren about poison ivy -- "leaflets three, let it be!"


Back to Weed Menu
Back to the Hortiscope Table of Contents