All of the Vines
Considering that the vines can pop up out of nowhere and strangle (a lot) of people.
I doubt anyone really feels like “I IZ POKE U VINEZ!” is a great idea, especially ones that seem to be feeding off energy, that may be going straight to Mord.
Imagine someone tried to slap a perfect sandwich out of your hand right as you were taking a bite.
Mord is sitting on a ley line. All of the waypoints that have the vines next to them are sitting on the ley line as well (can be seen via looking at scarlett’s probes). They are corruption from him spreading (one can even be seen in Lion’s Arch)
Seeing as how they are stated to be simply a part of a larger body (Mordemoth) I think it’s safe to assume it’s not that simple to cut them down.
They’re not just vines, they’re parts of Mordemoth himself. Ii might be a bad idea to just go and attack one.