By Jason Griffin, Extension Specialist, Woody Ornamentals & Industrial Hemp
Here is one we have just been itching to write. How do you control poison ivy?
Recently we have had a rash of questions about this topic. During these warm days of summer poison ivy can grow at a blistering pace, so don’t delay treatment.
We all know the plant. Leaves of three let-it-be. A vining menace in the landscape that quickly gets out of control because no one volunteers to control it. For those unfortunate enough to cross its path, skin rashes, weeks of itching, and a steroid prescription may follow if it gets bad enough. Yep…been there.
The good news is that it can be controlled with some commonly available chemicals. Yes, it can be removed by hand if you are one of the lucky resistant individuals. Yes, goats will eat it too. However, our topic here is chemical control since most of us are susceptible and don’t have ready access to a herd of goats.
Glyphosate will take care of poison ivy, but in my experience the kill is slow, incomplete, and needs reapplication, but it does work. If you want faster and more complete kill, there are other options. Before we go there, remember, glyphosate and any tank mix with glyphosate will kill almost any plant you spray it on. Know what is in your tank and what plants it will impact.
Keep in mind that poison ivy is a broad leaf perennial plant. Products that eliminate poison ivy will be harmful to other broadleaf plants. If you have poison ivy vining and growing among your desirable plants, chemical control may not be a good idea.
Our ‘go-to’ when we need to kill a heavy poison ivy infestation is a tank mix of Crossbow (triclopyr + 2,4-D) and glyphosate. It has never failed. Keep in mind that this mix will kill any plant it gets on and 2,4-D can volatilize and damage off-target plants, especially on warm summer days. Use it with caution, know your wind direction, and maybe have a dedicated sprayer just for this purpose. This combination typically results in rapid and complete kill. Crossbow (and its generic versions) will also take care of poison ivy very efficiently by itself. We use it in areas where poison ivy has mingled with any grass we want to keep, such as a brome hay field or an area prone to erosion where we want to keep the grass. There are also products available that contain triclopyr as the only active ingredient. We have used those in the past as well. They do work, but we typically reapply or tank-mix with glyphosate to get the desired result. Again, know your chemicals. Triclopyr by itself will not harm grass, but a mix with glyphosate will kill most plants.
Dormant treatment is also possible in heavily infested areas. Crossbow (and its generic counterparts) when mixed with diesel (instead of water) and sprayed on the stem when the plant is dormant will kill poison ivy. We use it along our fence-line where the poison ivy has completely covered the chain-link. Generally, we target this treatment for mid-March, just as the poison ivy buds are starting to swell. Treatment is most effective as plants are coming out of dormancy. Spraying with diesel feels wrong (I know), but it is on the label, and it works when desperate times call for it. Be aware that this combination will kill almost anything it is sprayed on, and your sprayer pump manufacturer will strongly recommend against running diesel through it.
Plants are most easily controlled when they are small and young. A ground cover of poison ivy can be controlled more easily than a plant that is vining up a nearby tree, fence, or building. Procrastination leads to larger plants with thicker stems and a more robust root system that needs more aggressive measures. Also, birds like to eat the poison ivy fruit and spread it. Control prior to flowering and fruiting is advised.
A recent trip to the local big box hardware store had several products that will take care of poison ivy. Some are sold specifically for poison ivy control, but there are other products with the exact same active ingredients. Check the label and you may be able to save a few dollars by doing some homework.
Good Luck!
For many years, Round-Up herbicide was recognized as a non-selective herbicide that contained glyphosate and was used to take out all vegetation. Round-Up is now sold as multiple different products containing many different combinations of herbicides. The University of Tennessee team recently composed a document that provides details on Round-Up. All should pay close attention to active ingredients contained within each Round-Up herbicide now sold.
Photo shows crabgrass emerging in Olathe, Kansas near a paved walking path in a park area. Greater soil warmth allows for earlier emergence in these areas. The photo was taken on April 21.
This new blog video gives an update on a research project, a turf-related issue, or current concerns in the turf industry. Each one will be approximately 2 minutes long – you’ll see one periodically!
