Saint Nectan's Kieve is believed by some to be a sacred place or cloutie well, and numerous ribbons, crystals, photographs, inscriptions, prayers and other devotions now adorn the foliage and rock walls near the waterfall. Many visitors add small piles of flat stones obtained from the stream.

https://en.wikipedia.org/wiki/St_Nectan%27s_Kieve

A clootie well is a holy well (or sacred spring), almost always with a tree growing beside it, where small strips of cloth or ribbons are left as part of a healing ritual, usually by tying them to branches of the tree (called a clootie tree or rag tree). Clootie wells are places of pilgrimage usually found in Celtic areas. It is believed the tradition comes from the ancient custom of leaving votive offerings in water.

https://en.wikipedia.org/wiki/Clootie_well

A wish tree is a tree, usually distinguished by species, location or appearance, which is used as an object of wishes and offerings. Such trees are identified as possessing a special religious or spiritual value. Postulants make votive offerings in hopes of having a wish granted, or a prayer answered, from a nature spirit, saint or goddess, depending on the local tradition.

https://en.wikipedia.org/wiki/Wish_tree

Bonus:

She loves it. :)