A favorite May herb is the hawthorn, also called May, a small shrub that blooms with white flowers at this time of year. For many, it is sacred, perhaps from the tradition that Christ's crown of thorns was made from its branches. It takes its name from the German word for hedge (hage), because the Germans used the thorny shrub as a hedge, to divide their fields, and its flowers were gathered for May Day celebrations. Since the 1700s, the herb has been used as a cardiac tonic to regulate blood pressure and to treat coronary insufficiency (the weakening of the heart muscle due to aging).