Since you pulled up bunches, perhaps you could share some more details about the plants. Did it have vines, underground runners, a single/entire leaf or leaflets, etc....

It is kind of hard to figure what Seussian grape leaves look like. ;)

FataMorgana

I have no idea but here in NC we have a lot of this stuff on the ground right now...sort of grapish (green/yellow) fruit and distinctive leaves? I know this plant is also found in NH.

What colour are the "grapes" of your unknown? Any other characteristics you can think of would help...I'm sure someone here will guess what you're seeing :)!

Here is a link that might be useful: horse nettle

a wild guess....
?porcelain berry
Ampelopsis brevipedunculata

Here is a link that might be useful: pca least wanted - porcelainberry

two things ...

first.. pulling up.. such an aggressive plant.. rarely works ... and often causes it to multiply ... you might want to rethink your effort .. until you have an ID ... i would drip roundup.. on cut stumps and insure killing it ... i try to work hard.. only once ... [unless of course.. you are sure you are getting most all of the roots on a given plant]

second ... other types of vines like to hide in large ramblers.. and i am thinking poison ivy in particular ... be careful when doing such.. be sure to be able to ID such ...

a call to your COUNTY extension office.. might get you a fast ID ... if its as common as you think.. or even carry in a leaf ... they may also have ideas for eradication ...

ken

...or better still, ID the thing before you go on a destroy-all mission. I kinda think we should know what we're dealing with......you know, before we deal with it.

+oM

Any chance it is just a wild grape? Can be aggressive is a good native wildlife plant in the right spot.

Here is a link that might be useful: wild grape