Brits really love their ivy.  

The Woodland Trust, self-identifying as the “U.K.’s largest woodland conservation charity,” portrays this climber as “clingy, luscious, misunderstood.” They explain that, “Ivy has long been accused of strangling trees, but it doesn’t harm the tree at all and even supports at least 50 species of wildlife.” The trust further insists that ivy covering buildings keeps the structures cool in the summer and less damp in the winter.  

Across the big pond, ivy — scientific name: hedera helix — is not so revered and its effects are disputed. In this country, ivy is considered an invasive strangler and can damage trees by shading their leaves and reducing photosynthesis. With the weight of the mighty ivy vines and leaves, the tree could get dragged down by wind and/or ice, as the ivy mass serves as a sail pulling the tree until it bends and snaps.   

On the ground, ivy can crawl and cover the ground surface, prohibiting water penetration and leading to erosion, especially on slopes. Nor is it an easy or pleasant walking surface.  

Structures are at risk with ivy’s spirited upward sprint. At its most energetic, ivy can go up, up, up — even 80 feet high if it has something on which it can ascend.  Buildings, chimneys, walls and fences can fall prey to this vertical vagrant that can weasel its way into wood and mortar and cause structural damage. Add to this ivy’s propensity to harbor small mammals, such as rats, and it can bring bad luck to any property owner in its path.  

Ancients had no such concerns with ivy, believing it a potent and positive plant. It was taken into homes to drive out evil spirits, given to newlyweds as a symbol of fidelity, and believed to promise eternal life. Romans used it to signify intellectual achievement, and winners of poetry contests and athletic competitions were crowned with wreaths made of ivy.  

Imbued with magical powers, ivy was believed to prevent a person from drunkenness and was worn by Bacchus, the god of intoxication. To encourage customers, British taverns of old and even today had an ivy-wrapped bush or pole outside of the establishment as advertisement of their alcoholic amenities.  

This year-round greenery is a very later bloomer. Its flowers come toward the end of autumn and into early winter, so it is not surprising that the fruiting umbels are easily seen into the new year. Those unique-looking fruits can be eaten by mammals and birds, allowing this non-native species to easily spread in those animals’ droppings.  

Ivy plants can look distinctly different, even if they are of the same species or from a solitary individual. Two different leaf types can be present on one plant mass and indicate age and maturity of its parts. Palmately-lobed leaves are found on juvenile plants and can be confirmed by their slender, flexible shoots with small aerial roots. Thicker, self-supporting vines without aerial roots are adult plants and have unlobed, cordate — meaning heart-shaped — leaves.    

Native to Europe, northern Africa and Asia, ivy found its way to our shores with colonial settlers. It is considered invasive to different extents across the country. It is also appreciated for its year-round foliage and holiday associations.

Its success is not surprising; after all, with its pedigree, it is definitely in the Ivy League.

Suzan Bellincampi is Islands director for Felix Neck Wildlife Sanctuary in Edgartown and the Nantucket Wildlife Sanctuaries. She is also the author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.