Spread of imported fungal diseases poses threat to Britain's gardens

The National Trust has warned the Government that drastic action must be taken to curb the invasion of two deadly fungal diseases which could affect all public gardens in the UK within 20 years.

The experts have discovered the diseases have already jumped from cultivated shrubs and trees to native British species in important natural heathlands – such as wild bilberry. Studies have also shown the diseases attacks heather.

The diseases are caused by two species, Phytophthora ramorum and Phytophthora kernoviae – believed to have been imported on ornamental plants. The fungi are deadly to woody plants and shrubs including rhododendron, viburnum, magnolia and camelia. Experts fear their spread could become unstoppable. The National Trust has written to ministers calling for swathes of rhododendron to be cut down to stop the spread.