Some people think that a building covered in ivy has a certain romantic charm. Others worry that ivy will tear apart the walls on which it climbs. If there’s ivy growing on your buildings, you may wonder if you should be worried. The answer is… it depends.

Ivy is a rapidly-growing self-clinging climber that can quickly cover walls, fences, and even entire buildings. It may overshadow doorways and windows, and entrap drainage downspouts and gutters. If ivy is thick enough, it can even create cover for intruders, or homes for pests like mice and other rodents.

But those issues aside, will ivy actually hurt the structure of your building? More and more research shows that ivy itself usually does very little damage to masonry. It is true that ivy grows by sending roots into cracks and crevices, but most ivy isn’t strong enough to create those cracks by itself. There are certainly many a charming crumbling cottage covered in ivy, but the ivy was able to thrive because of many cracks, it wasn’t the cause of them. Ivy is good, however, at wedging its way between boards and shingles, so keep it away from wooden siding.

A study by Oxford University found that not only is ivy generally not harmful, it can actually be a beneficial and money-saving part of your landscape. Oxford’s three-year project found that “ivy acted as a thermal blanket, warming up walls by an average of 15% in cold weather and cooling the surface temperature of the wall in hot weather by an average of 36%. The ivy was also found to absorb some of the harmful pollutants in the atmosphere. Walls where ivy was growing were less prone to the damaging effects of freezing temperatures, temperature fluctuations, pollution and salts than exposed walls without ivy.”

The final verdict? If your masonry is in good repair, you have little to fear from well-pruned ivy. In fact, you may even consider planting some for its beneficial effects. On the other hand, if your walls are a little worse-for-wear, it may be smart to remove the plants and prevent further damage.