The best thing to do with the poison ivy vine which I assume you will want to get rid of, is cut it.

If it were mine I would take an axe and cut it at ground level, and then again as high as I could reach. I would use an axe as it has a long handle to keep me away from the vine. I would put the section I cut out into the trash. DON'T burn that piece of the trunk as you can get poison ivy from the oils in the vine.

Once cut and taken care of I would go take a shower soaping from head to foot, twice to insure I did not get poison ivy.

@floral_uk - yes we’re new to the house! Oh my - that’s poison ivy??!

Yes and I have seen them three times larger diameter. If the previous person just sprayed the ground, odds are that the vine will not die. There for it has to be cut as I said previously.

Thank you @krnuttle - but how does this explain the plant death around the tree? Maybe I’m missing that part...

killing a vine ... done properly .... involves cutting the vine near the ground.. and apply 100

% roundup or some other stump killer ... it is not a spray diluted weed killer on it ...

someone above suggested someone tried to spray it.. and it drifted around... killing other things ... improperly done on two levels.. dilution and application ..

i would cut.. and not with an ax or hatchet near the ground... and immediately apply killer ... and then cut as high as needed so lets say kids cant get to the upper part ... no need for killer for upper part ... its already dead after cutting ... and get rid of the lower part .. and then just leave the rest hanging in the tree.. do not hurt the tree trying to pull it out .. been there done that with grape .. lol ..

i would wear long pants... long sleeves.. and tape heavy duty rubber or vinyl kitchen gloves on the wrist ... and then immediately wash it all in hot soapy water ... not 7 hours later when im done in the yard.. or do this last ...

and id probably wear heavy duty kitchen gloves .. and while they are still on.. wash them down with dawn ... your dealing with an oil .... so the dawn will do the job on rubber or vinyl gloves ...

and im not even allergic to it.. that i know of.. and i dont want to find out ...

the tree .. you probably need an onsite inspection by a certified arborist .. which isnt just any woman with a chainsaw.. invest a few buck in a good independent opinion ...

ken

add your city and state to the search terms

https://duckduckgo.com/?t=ffsb&q=isa+certified+arborist&ia=web

oh.. and.. with a tree that big ... if there was a drought last year.. it could have dominated all the smaller plants with its massive root mass ... so that another possible reason why shallow rooted plants fail under a large old tree with aggressive roots ...

i dont feel like scrolling up;.. did we ever id the tree???

if you try to dig a hole out there.. and cant get a shovel into the ground.. that will answer how bad the roots are ...

btw: keep in mind that PIvy roots also have the oil .. so dont do a lot of digging out there unless your are protected with at least gloves .. though you dont have to get carried away like my prior post.. a little prevention is worth a lot of cure ...

dollar store disposable work gloves can just be thrown away... for lightweight protection ...

ken

That's how stuff grows under a pine tree, don't see anything out of the ordinary there. Maybe some low bush blueberry or black huckleberry would survive under there if you did everything right.

Thank you very much everyone! I will be both contacting an arborist and tackling the poison ivy vine.

The tree is an arborvitae.

Thuja was my first thought too.

Oh yes that’s poison ivy!! Argh!! See all the hairy hairs on it?

I would guess someone poured some kind of herbicide at the base of the tree/vine and it’s slowly killing everything around the tree.

I don’t know how susceptible to it you are, but I’m extremely so. My only choice would be complete removal of the tree and vine. By someone else. While I was gone on a two week vacation.

The arborvitae's foliage looks very scant....

there are actually other explanations

Pachysandra is susceptible to boxwood blight, for example

A typical layperson would not have known how to access a herbicide that would have caused this kind of kill pattern, where the tree stays alive...which it presumably is

OP just moved in so we don't even know if the PI vine is alive or not!

finally, I've seen this kind of dieback pattern in ground covers where an evergreen prevents the accumulation of snowcover directly under it, allowing more winter dieback close to a trunk.

PI is dangerous but it's not freakin' plutonium...reasonable precautions can be taken without highly specialized equipment. I have cut them off with chainsaws and pruning saws and never had a problem. You just make sure you stand well clear of the chainsaw's chip spray or whatever its called. Then, clean the sprocket cover and chain using gloves; I rinsed the chain with old stale gasoline I had in my garage from the previous owners. Reinstalled it with gloves and continued cutting other things. The bar oil will dilute any irritant that is left. (I do now remember that for the biggest, baddest one I ever cut, I wore a N95 respirator and chemical spray goggles just to be on the safe side. It was 3-4 inches thick! But not for most of them)

The cut vine end is easy to kill as vines go...triclopyr or glyphosate will work...I even once used lesco 3 way amine. Mix undiluted with a few drops of detergent or horticultural surfactant and apply with an oral irrigation syringe or similar. Done it many times without killing the tree.

Quote: "My only choice would be complete removal of the tree and vine."

There are three separate things going on with this tree. Yes there is dead things around the base of the tree but several explanation have been offered for that.

The poison ivy vine has to go, From experience, the doctor told me when I visited him, the only place you can not get poison ivy is on your eyeballs. which is a small consolation when it is everywhere else. And yes in certain situation you can give poison ivy to other people. I got it several time because the dog had gotten it on his fur and I petted him.

Lastly with the information provide, there is Absolutely no reason to cut down the tree. It is a strong feature in your yard, and would be a significant loss if it were gone. In a few years after you get to know the tree, if it has a fatal disease they you can consider if it is necessary to take it out.

Thank you so much @krnuttle and @UpperBayGardener (zone 7) - this makes me feel so much better! I'm going to tackle the poison ivy and leave my beautiful tree as is for further observation (and enjoyment!).

im lazy this morn.. want it suggested you hire an isa certified arborist for an evaluation of said tree .. if not.. ill say it now ..

the crown of the tree.. based on these not great crown pix.. looks very sparse.. and not very healthy .. and its a huge tree .. if it falls down.. will it fall down on anything important ...???

i suggest you invest in an on sight inspection.. and then enjoy it.. or remove it.. based on relevant information.. rather than a hope and a prayer ....

ken

https://www.treesaregood.org/findanarborist/arboristsearch

The Pachysandra is drooping and yellowing in a clearly delineated circular patch around the tree. If Pachysandra reacts to Box blight in the same way as Box that is not what the problem is here imo.

If I try to put myself into the mindset of someone extremely stupid and ignorant, I suppose he (or she) could have been afraid to touch the PI at all, and doused the ground with an herbicide active on roots like imazapyr or picloram. Not realizing or caring that it could have killed the tree too. But we just don't have enough info here. The poorly lit picture up at the foliage does seem to show a thin crown, but old Thujas can just look scraggly like that especially ones that are in the shade of other trees. We actually see what look like a couple scraggly canopies in that picture.

It appears to have totally lost its 'value' as a screening plant, which is probably why it was planted 40+ years ago...so the OP has a choice to make regarding whether to keep it or not, anyhow.