The Glastonbury Thorn is a curiosity of the natural world dressed up in legend. The Crataegus monogyna 'Biflora' variety does indeed flower twice a year, with a delicate winter blossom in time for Christmas. A flowering sprig is cut every year and sent to the reigning monarch.
Several specimens grow around town: one inside the Abbey grounds, one in the churchyard of St John the Baptist on the High Street, and one on Wearyall Hill where Joseph of Arimathea is supposed to have first planted his staff. That last tree was vandalised in 2010 and has struggled since, but cuttings are being nurtured. The Abbey tree is the most reliable place to see it in winter bloom.