Is this poison ivy growing in my garden?

Question

Its growing quite tall, and has some very large leaves. Def leaves of three, but I never knew poison ivy could be so large.

Answer 1

The small leaves are poison ivy; the large leaves don't look like it but could easily be an aberrant leaf form. Obviously, if they're connected to the small leaves, then they are poison ivy. RoundUp will indeed knock it back so that it looks like it's dead, but it usually just resprouts in a month or so. You'll probably have to spray several times to actually kill it.

If you find that RoundUp doesn't ultimately work, you can use a chemical control on the cut stem, as crazy as that may sound. Because only the sap contains urushiol, the chemical that causes the reaction, it is possible after the leaves have dropped in the autumn to cut the vine with little chance of a reaction (no or little sap remains in the stem at that time). I would consider this to be a semi-safe process (i.e. wear nitrile or rubberized gloves and eye protection). After cutting the vine, brush triclopyr (AKA Stump and Brush Killer) onto the cut end of the vine and down the stem to the ground. Use alcohol wipes to clean the triclopyr container and its cap, your gloves, and your secateurs after you do this, then dispose of the wipes in the garbage, not a firepit. I'd leave the cut vine on the ground to rot. As noted elsewhere never burn poison ivy leaves or vines.

Answer 2

That does indeed look like poison ivy to me, and not any of the look-alikes I know of. The leaves are larger than I've seen before too, but I've read they can be up to 7 inches long and 4 inches wide. That seems in line with what you're seeing.

Good luck and stay safe!