In April 2016, the garden was forced to close temporarily as a result of structural damage to the terrace wall, following the collapse of an old mining tunnel in Earlham Road. The garden reopened on 23 April 2016. After three sinkholes opened up near the garden, Norwich City Council arranged to carry out underground probing work at the site, which was planned for 31 January 2017. Entrances to the garden were sealed off on 28 January. After further safety tests the garden reopened to the public on 15 March 2017.