So this weekend, the weather was gorgeous, unseasonably warm. So we’re all out in the yard–I’m getting the garden ready for tomatoes, the lestrangelets are experimenting with garden hoses and mud, and Mr. lestrange is contemplating what destruction he can wreak on the trees in the yard. The biggest is a maple near the house. Its trunk is covered with ivy. Very pretty. So Mr. lestrange says to me, “That tree won’t last long.” Why? I ask. “Look at all that ivy!” Huh? It’s not covering leaves or anything, just hanging on the trunk, looking picturesque. He insists that the oil in the ivy leaves leaches into the trunk somehow and eventually poisons the tree. I do recall reading somewhere that it used to be believed that ivy would kill trees, but that it was a myth. Mr. lestrange doesn’t buy that–“why is everything I say a myth, but you’re always right?” he asked. I was tempted to say, “Because everything you say is a myth, and I’m always right.” But I value a peaceful household more than the opportunity to be a smartass.
So what’s the deal? Will ivy growing on the trunk of a tree kill it?
I can’t say for sure, but I think Mr. Lestrange is on a myth. I’m not a botanist, but the only ivy I know of that can kill trees is English Ivy, but not by poison. If poison ivy killed other plants, I think it’s safe to say that there would be very few other plants around, or at least, trees with poison ivy growing on them would have the same effect when you touched them instead of the ivy.
No, the oils wont kill the tree. More likely the vines would strangle the tree first. Anyway, here in Monterey, Poison oak, which is a different species, but same genus (Toxicodendron), frequently climbs up into the Monterey pines, and the trees are alright. It’s actually kind of pretty, and keeps people out of the trees.
It is also true that english ivy, and other ivies will kill a tree. Sometimes they shade out the canopy, often their vines end up girdling the tree, killing it. Not to mention it allows rats and other vermin a nice place to make a nest.
I think the OP just used the words “Poison Ivy” to be cute and artistic (I think she succeeded). Her maple tree is NOT covered in poison ivy she is just wanting to know if the IVY is POISONING her tree. From the previous replies, it looks like it won’t poison the tree but could still kill it.