English Ivy, a traditional ground cover, has been scaling buildings and reaching new heights since the advent of man-made structures. The fast growing vine clings to and eventually overtakes old structures and trees. It creates a unique look shared by most historical buildings, Ivy League schools, and of course Wrigley Field. But, with so many older structures engulfed in the plant, what effect does the Ivy have on what it climbs? It was a serious question posed by a conservation team at Oxford University. The vast majority of historical buildings in the UK are covered by Ivy, so naturally scholars wanted to find out the plant’s effects on such rich history.
Their hypothesis was that over time English Ivy damaged buildings and trees. It was evident the old stone buildings were deteriorating, but was this merely an effect of time or was the Ivy to blame? After three years of studying, what they found was quite interesting. They discovered that Ivy can be harmful to a structure or a tree, but only if the host (for lack of a better word) is already damaged or in decline. I just used the word “host” but Ivy actually isn’t parasitic, it establishes itself by extending tendrils and rooting themselves everywhere they land. And here lies the “root” of the problem.
If you have a healthy structure, then the Ivy will subsist on the surface without risk. In fact, researchers found that Ivy-covered walls (in relation to bare walls) were 15% warmer during the winter and 36% cooler in the summer; casting Ivy as a versatile insulator throughout seasons. Their research concluded that healthy trees sporting ivy vines weren’t at risk either. The Ivy merely used the trees as a living ladder; scaling the trunk and branches until reaching the canopy. The vines also provided birds with much-needed shelter and food (in the form of berries) during the harsh winter months. Unfortunately for English Ivy, the positives end here.
Once Ivy reaches the canopy it begins competing with the tree for vital sunlight. It inadvertently suffocates the sunlight-starved leaves, preventing photosynthesis and leading the tree to its eventual death. Structures suffer the same fate, but the process is a little more complicated and drawn out. Ivy roots burrow into any crack in the foundation or walls, accelerating the process of decay. The vines squeeze in between vinyl siding and dry-stacked walls, remove paint and stucco from walls, and damage gutters. The openings created by its roots allow entry for other pests and insects.
English Ivy is a bittersweet vine; its elegant tendrils scaling the side of old stone and trees are a sight to behold. However, it’s that same Ivy that will ultimately be those buildings/trees downfall. Whether you have Ivy growing on the side of your home, or you would like to incorporate the look in your landscape, I would caution against it. Even if your building is new, and the bricks are in excellent shape, they will eventually falter or crumble and the Ivy will take advantage. I would advise using English Ivy as a ground cover, as it was intended, quarantining the plant to controlled areas and limiting its grip on those nearby.