Kill Poison Ivy but not English Ivy

Eileen from Concord asks:
There is a large patch of English Ivy around some trees in our back yard. It is becoming over run with Poison Ivy. I am highly allergic and do not want to get too close. What can I do to kill the Poison Ivy? Will I be able to kill the Poison Ivy and not the English Ivy?

A. Unfortunately, there isn't a chemical that you can use as a general "overspray" that will kill the poison ivy and not harm the English ivy. You're stuck with having to use a non-selective herbicide to spray on the poison ivy leaves, while trying not to get it on the English ivy leaves.

I suggest using an herbicide that contains glyphosate. This is what I use at home, and you can purchase it at a hardware, garden center or building supply store. I mix up a small amount (ALWAYS follow the directions on the label!!) in a squeeze-trigger spray bottle and carefully "dribble" it on the leaves of the weeds I want to kill. You can also mix it up in a coffee can and dab or paint it on the leaves.

You can help keep the glyphosate off the English ivy by holding a piece of cardboard under the poison ivy leaves. Cut out a notch so that you can slide the cardboard around the stem beneath the leaves. If a little bit happens to get on the English ivy it probably won't do that much harm, anyway. A sufficient amount of the chemical needs to be applied to a plant for it to work, so a drop here or there shouldn't matter. I know I've gotten a little on my ivy at home, and it didn't bother it. A couple leaves turned brown, but that was it.

Glyphosate takes 2-3 weeks to work, so give it time. You may want to do a treatment once a week for 3 weeks, treating any new leaves that may emerge during this timeframe. Glyphosate kills by working its way slowly down to the roots and killing the entire plant, but it doesn't move into the root system of an adjoining plant, so no harm can come from that direction. It can only kill the plant whose leaves you have sprayed.

If you have young or thin-bark trees within the poison ivy, be careful not to get spray on the trunk. Although it probably won't kill the tree, the chemical can be absorbed into the bark and kill off a patch of it, which isn't good. Also, avoid getting spray on any suckers that may be growing from the base of a tree. Clip the suckers off first if you think you may.