Mythbust: the IVY Controversy

I have a lot of ivy in my garden, both on walls and as ground cover.

As you can see it's plain English ivy, nothing variegated, so when I had a bit of time this week I cleared some of this to make way for some new shrubs. You can read about these on my other blog post: Plants for Shade.

I mentioned to a friend that I had been doing this and she immediately launched into a tirade about what a nuisance ivy is, especially on walls. I have a neighbour who asks me to clear ivy from our party wall because he's concerned that it may cause damage. So I thought it was time to address the Ivy Controversy: does it damage walls or not?

First of all let me state my position: I am not an ivy hater. I don't mind it as ground cover while I'm waiting to develop an area and I love it on walls, although I clear it off the one where the neighbour dislikes in in the interest of maintaining a good relationship with him. I prefer more fancy varieties but I tolerate the plain type.

The view that English ivy can damage walls remains common among garden experts, but it always seems to be based on observation rather than science. The problem with this is it's difficult to tell whether the ivy damaged the wall or it was already damaged and the ivy has simply taken advantage of this; I've challenged several experts on this topic and none has been able to provide any actual evidence to support their belief. On the contrary, in 2010 a three year study commissioned by English Heritage and carried out by Oxford University concluded that ivy can actually protect walls from damage by insulating them from temperature and humidity extremes (https://www.tandfonline.com/doi/abs/10.1080/13556207.2011.10785087). It's true that if a wall is already damaged ivy stems or roots may find their way into cracks but they did not cause the initial damage.

In my personal view, ivy is more attractive than a brick wall, protects the wall itself and the only downside to it is it may need to be removed if the wall it is growing on needs inspection or maintenance work.