Hmmm...grass might out-compete PI, I suppose. But that would be a battle that isn't really worth fighting. Just spray or pull it and start from scratch.

If you do find something that you can plant that will outcompete it, please let me know!

I'm not far from you so I can tell you that in your area poison ivy is one of the few native plants that thrives, I've even seen it growing up through english ivy. I think you would need to first thoroughly kill what poison ivy is there and maybe then something would hold the ground like ferns or shade tolerant sedges or grasses but I'm not even so sure about that. Some plants, like virginia creeper, can coexist pretty well with poison ivy but few will eradicate it.

NOTHING outcompetes poison ivy. I use round up on it without mercy. The roundup will not likely hurt a tree except a sycamore or other tree with exfoliating bark. I also snip (ask DH to snip) big vines near the base of the tree. And then I go back year after year with my round up. GOod luck!

You can't outcompete Poison Ivy thoroughly enough to prevent it from growing altogether. I suppose lots of plants might, once established, keep the poison ivy from growing thickly, but there will always be a few PI leaves sticking through that can give you a rash. IN fact, if you have other thick vegetation, especially things that look sort of like PI such as English Ivy or Virginia Creeper, it makes the PI eveh harder to see and avoid.

You might try a vinca. I had a big poison ivy problem. At first, I had to keep after the PI with the spray. My nearby vinca started creeping in while the PI was wounded. It's so thick there now that it won't let anything else grow there, including the PI, grass, and all kinds of other weeds. Just a suggestion.

Vinca is worse than PI once it gets started. The natural area across from me has vinca crawling all over in about a 15 acre area. Since the birds eat the berries and poop the seeds in several areas it is considered right next to japanese honeysuckle.

There is still PI in that section of woods just creeps under the vinca's leaves the shoots up the trees.

vinca, myrtle, perriwinkle, etc. is highly invasive in the Hudson Valley area.