Controlling Poison Ivy with Organic Sprays

Hi Doug,

I live in central Illinois and bought a 10 acre piece of land loaded with poison ivy. I removed a good portion of the vines over the winter, but it seems to have reemerged heavier this spring.

I've tried Ortho Brush-B-Gone and Round-Up with very limited success. Someone also told me to spray it with a 50% brine solution, but I haven't tried that yet.

What do you recommend to kill the poison ivy (pulling it out at this point doesn't seem to be an option :)


Doug says

Here's where I start to have problems with organic controls. It is really, really tough to control woody plants with organics. But for what it's worth...

Leaf "Burn" Organic Chemicals

You can use an organic herbicide containing acetic acid. There are different products of this stronger than vinegar acid - a commonly known one is 'Sharpshooter'.

These are "burn" defoliators and will act like a chemical burn agent taking off the leaves so the plant can't obtain energy from them.

Repeat Regularly

The kicker in any burn (chemical or organic) is that it must be regularly repeated for at least one entire season whenever leaves are produced anywhere on the plant. Consistency is required and it may take several seasons to fully kill off the plant (I'd be surprised if you got it in one season).

This would be the same thing for Roundup (see below)

I won't comment on Brush-B-Gone as this is really ugly stuff and I'd never use it anywhere on my property no matter the plant.

Roundup or Glyphosate

Roundup is a hazy area for me. I know the active (glyphosate) has some negative press and the fillers are deadly witches brew but... in limited spraying it is probably the least offensive of the chemical sprays.

I'd never recommend using it as a general spray but it could be effective in specialized applications.

On woody plants it has to be used at the highest label strength and usually repeated several times. Frankly, it is not as effective as the advertising would have us believe on larger woody plants with established root systems.

organic weed control
Poison Ivy courtesy Wikimedia

Painting It On Freshly Cut Trunks

It is much more effective painted full strength onto the stumps of freshly cut woody plants. You wouldn't have to pull them but cut them at their base; painting the fresh cut with the roundup "oil" at full strength is a registered label use and will kill the average plant with a single application.

But If You're Spraying?

And if you're spraying multiple times, why not use the slightly more expensive but much safer organic alternative.

So there you have it. The problem with a noxious plant is that it will require multiple sprayings of either chemical or organic treatments. Or a painting with full strength Roundup concentrate.

A final note - whatever you spray, you're going to have to wear protective clothing and proper masks. You're wafting fine nozzle droplets into the air and you really don't want to be breathing either the chemical or organic sprays.

Resource for High Potency Vinegar

You can now buy 20% vinegar by the gallon for serious weed burning

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