Hawthorn is significant in Celtic folklore. In Ireland, where the shrub is known as The Fairy Tree, hawthorn is said to be a portal to the fairy realm. Its flowering coincides with Beltaine, or May Day, at which time the tree is adorned with clottie—strands of ribbons and trinkets—in the hope that the fairies will grant special favors to those who leave them.
The active component of hawthorn berry powder is hyperoside, a glycoside derivative of quercetin. This explains why the herb has a long association with the heart. The German Commission E, the European equivalent of the FDA, has approved of the use of the herb to counter cardiac insufficiency.
