I recently went hunting in an area that had a big patch of hawthorn trees. Curious about the trees, I did some Googling and learned about superstitions surrounding the tree that I was never aware of.
First off, hawthorn trees, or simply called haw trees in some places, are short shrubby looking trees that are covered in thorns. They are popular in Europe for hedgerows and Germany is full of them. They can live to be 400 years old and are a hearty tree able to thrive under harsh environmental conditions and poor soils.
It is rumored that the crown of thorns placed on Jesus during the crucifixion was made from twigs of the hawthorn tree.
The Irish believe that fairies live in hawthorn trees, so it is bad luck to damage or uproot one, especially if it is a lone hawthorne tree standing by itself. A highway in Ireland was even diverted around hawthorn tree because they didn't want to uproot it and give all the travelers on the road bad luck.
A hawthorn tree is a passage to the otherworld. Oaks and elms are also spiritual trees, so if you have an oak, elm and hawthorn tree in the same place, you have some powerful mojo going on.
Witches are said to make their brooms from the branches of hawthorn trees.
In many cultures it is taboo to bring the pretty blooms from a hawthorn tree into the house because it will bring a death to the family.
The hawthorn tree was made into Maypoles for pagan celebrations back in the day.
One of Christopher Columbus' ships was named the Mayflower, after the hawthorn tree, which is also called the Mayflower tree, since it blooms in May and signifies the end of winter and the coming of the summer solstice (important to pagan cultures).
Magic wands and walking sticks were made from hawthorn trees (and still are). But you must state your intention to the fairy inhabitants of the tree and only cut with respect and reverence, or else suffer the wrath of the fairies.
Fisherman would carry a thorn from the hawthorn tree in their pocket to assure a plentiful catch.
Etc.
Pretty interesting stuff.