Poison ivy (Toxicodendron radicans) is a native vine common to woodland areas but found frequently growing in gardens and along fence lines. This vine causes an allergic reaction (dermatitis) in most people when their skin comes in contact with urushiol produced by the plant and present in all parts of the plant including leaves, stems, and roots on both living and dead plant material.
Control of this weedy vine requires special consideration. When working around this plant, gardeners should wear long sleeves and pants with waterproof gloves to protect the skin from the urushiol oil.
The best control for poison ivy is to monitor frequently and remove plants promptly when they are found to avoid vines from becoming large and more difficult to control.
Only those plants that are very small should be dug or pulled. This method is done more easily after a soaking rain or deep watering. Utilize a trowel, spade, or weeding tool to dig and pull the plant out of the ground be sure to wear waterproof gloves and long sleeves.
This application method can only be used if the poison ivy is not climbing or rambling on a desirable plant as the herbicide will impact any green plant it comes in contact with. Systemic herbicides such as glyphosate or triclopyr can be sprayed on the foliage of the vine. Use all herbicides with care as they can cause damage to nearby plants if applied incorrectly. Leave vines in place to die and decay naturally in the garden as pruning, pulling, or otherwise trying to physically remove the vines, either alive or dead, can spread the urushiol oil, potentially getting it on the skin and causing irritation and rashes.
Consult the label carefully as not all herbicides are labeled for all garden settings. Always apply herbicides when winds are calm and temperatures are cool to prevent drift and damage to desirable plants. Protect desirable nearby garden plants with barriers like buckets, boxes, plastic bags, or plastic sheets to further reduce problems with drift. Herbicides must be used according to label instructions on the package.
For larger established vines, utilize the cut stump herbicide treatment to control this weed. Leave vines in place to die and decay naturally in the garden as pruning, pulling, or otherwise trying to physically remove the vines, either alive or dead, can spread the urushiol oil, potentially getting it on the skin and causing irritation and rashes.
Cut the vine off near the base and applying the herbicide directly to the cut surface as quickly as possible after the cut has been made and the sawdust has been brushed aside. Utilize a sprayer, squirt bottle, or foam brush to apply herbicide to the entire cut surface of the stump. Only use enough herbicide to thoroughly wet the cut surface and avoid runoff.
Applications of glyphosate and triclopyr at higher concentrations work well for this application method. Glyphosate should be at least 20% active ingredient and triclopyr should be greater than 8% active ingredient.
Applications can be made anytime during the growing season, although late summer and fall applications tend to be slightly more effective.
If the stump resprouts, cut and treat again or apply a foliar spray to the new growth. Multiple applications are frequently needed.