This is the Holy Thorn in the grounds of Glastonbury Abbey. It is a Hawthorn with the unusual property that it flowers twice per year, once at Christmas and once at Easter. The one which originally grew on Wearyall Hill was supposed to have sprouted from the staff of Joseph of Arimathea when he planted it in the ground. A tree was grafted and grown in the Abbey and has been regrafted numerous times going back many years. The specimin at St Johns is the one used for a sending a sprig to the Queen each Christmas time.