Common boxwood (Buxus sempervirens) line either side of the Sunken Garden, flanked by rows of American Beech (Fagus grandifolia) and Crape Myrtle (Lagerstroemia indica).

The disease was first identified in 1994 at a long-gone Hampshire nursery that specialised in Buxus sempervirens, or box. Some larger topiarised plants had been grown in moist, warm tunnels in ...