When is a plant likely to cause damage to a building? Will the damage be structural or cosmetic? Is structural damage caused by the weight of the plants or by water infiltration or by growth that lifts and displaces materials? All good questions, and all asked about three climbing hydrangea plants at corners of the Peter Heydon buildings on East Washington Street in downtown Ann Arbor.
In this case, the climbing plants were knowingly selected by a highly qualified landscape gardener for their beauty, heartiness, and inability to harm the historic masonry. Maintenance is required to keep the plants trimmed away from the wood fascia trim, the shutters, and the windows, but there is no concern about the weight of the vines impacting the masonry structure, nor is there any concern about the vines penetrating the mortar joints or masonry units.
Some plant materials, like English Ivy, can do great harm and should be kept off historic buildings. The little ivy “feet” dig into the mortar and weaken it, then allowing water to enter the joints and cause freeze-thaw damage, which can result in eventual structural damage to the wall.
Mr. Heydon takes great pride in his buildings and their landscaping. Given his care and foresight, they will be preserved for many years for all to enjoy.