Poison ivy : copper and sulfur for knockback?

Yup, I mow a fair amount of it too. Last year I learned a painful lesson though. PI oil stays on metal (like mower decks and blades) for quite awhile. I got a heck of a case of PI after changing my mower blades. Be careful


Full strength is not what you need! Not more then double strength. Full strength kills leaves immediately - they do not have time to send the poison to the roots. And this is what you need to kill it. You need to be patient with PI.


I’ve sprayed PI with 2oz. 41% gly concentrate per gallon water, 4 oz. 41% gly concentrate per gallon water, and 6 oz. 41% gly concentrate per gallon water. All yielded the same, unsuccessful results. PI died back, appeared dead, then resprouted from the roots and looked perfectly healthy again.

I can spray PI once with Crossbow at 2 oz. per gallon water and it is D…E…A…D…and it doesn’t resprout.


The poison ivy spray concentrate made by Bayer seems to be the best. Better than straight 2-4-d,

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For a Roundup substitute I prefer the Glyphosate by Bonide.

Works best in a side by side trial I did 2 years ago…with Roundup, Sprectracide, and the Ace Hardware product. And Bonide’s product.


Really? Would not have expected that.
Never know really effects til u look for yrself

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In addition to what others have noted about specific herbicides, there is some information in the UC IPM page on the timing of application.


Good to know. Thanks Vohd i bookmarked that page

I had a bad problem with poison ivy at my place when I first moved here. What seemed to really help kill it was adding some dollar store dish detergent to the herbicide mix as a surfactant. I think it helped break down the oily coating on the PI leaves and let more of the herbicide get into the plant.


I forgot to mention CROSSBOW in my post…old age I reckon.
Crossbow works just as well as the Bayer poison ivy product.
Both are way, way, way ahead of Roundup for poison ivy.


I’ve been using 41% glypshosate 2 oz per gal for the last 10 yrs with success. That may be because I’m only killing PI plants less than 1 yr old that have been seeded by birds.


Oh nice. I like that idea. Thanks

Ideally after i kill the current ocean i have thats where i will be at too.

Ty for the info on comparisons BlueBerry :relaxed: