Will Ivy kill my tree?

Jane Cornwall from Leeds has emailed me to ask if the Ivy growing up a young Oak tree will cause any harm.

Firstly, thanks Jane for asking the question and it is a subject we encountered often but I am afraid it does not have a single definitive yes or no.

Hedera in full blood

Firstly, Ivy (Hedera helix) is not a parasite and it does not actually live off of the trees resources but merely uses the tree as a support.

As Ivy grows it anchors itself using aerial roots and will grow high into the canopy seeking light. Contrary to popular belief Ivy it is not restricting the trees growth at all and will not constrict the trunk or branches.

As far as a woodland tree is concerned I would not worry at all as the Ivy is providing habitat and feeding for a variety of birds and of course the Grey Squirrel.

If you were to have Ivy growing into an ornamental tree then visually it is a problem and if left to run wild will restrict the light to the trees leaves and cause growth irregularities.

Ivy can also be a bit tricky to kill. Sulphate of Ammonia (lawn sand) will work and it pays to cut through the stem with a saw. Make sure you remove at least an inch (25mm) of stem otherwise the plant will 'weld' itself together again.

If you have a gardening or landscape question you need answering then email me at editor@landscapejuice.com

I get a lot of hits on this post from the United States so it seems appropriate that I have come across the Plant Conservation Alliance site that has an extensive write up about Ivy and the ways to control it.

Comments

[Noel Salisbury]

I dispute your statement that Ivy...'will not constrict' trunks or branches. I sawed through an Ivy stem at its base - it was a 4.5 ins diameter stem whih was growing up a 50-60 ft Oak Tree - and
simultaneously when I'd finished cutting-through the stem , - the stem on the upper side of the cut sprung away for about 2 ins. One could not push it back in situ, even with great pressure. Therefore the stem had grown & created tension,by itself.
Another name for this tension would be
constriction.
---------
When one removes Ivy that has been growing
around branches for a considerable time -
one can often see the actual indentations/
impressions marked upon the surface of those branches - in the same way as one
sees similar ones following the removal of
a Tree-Tie c/w stake after the establishment
of a young tree. We all know that where
such operations have been neglected, that
growth of the tree is curtailed,because there is a check on the trees physical growth systems. Ivy must check these sytems in the same hysical way.
beleive that