Chinese juniper vs Common juniper

It is one of the main hosts of pear rust (Gymnosporangium sabinae): the fungus overwinters in juniper branches, causes spindle-shaped swellings that push out orange, jelly-like spore masses in wet spring weather, and from there infects nearby pear trees (bright orange spots on the leaves in summer). If you or your neighbours grow pears, choose something else, and cut out swollen branches. In Central Europe the juniper jewel beetle has also become a serious threat in recent years: its larvae tunnel under the bark, shoots suddenly turn yellow, branches die one after another and oval exit holes appear in the bark; it mostly attacks drought-stressed plants, so remove infested branches and water in long dry spells. Tip blight can occur in wet springs and root rot in wet soil, and scale insects and aphids turn up now and then.

In Central Europe the juniper jewel beetle is now the most serious threat: its larvae tunnel under the bark, branches suddenly yellow and die, winding galleries show under the bark and oval exit holes on it, and a heavily attacked plant can die within a few years. Cut out and destroy affected branches and water plants weakened by drought, as these are attacked most. Columnar forms go bare and brown inside on dry, windy sites, snow splays them, and in polluted city air they get covered in scale insects. This species is not the host of pear rust, which lives on savin and Chinese junipers; common juniper carries related rust fungi that form orange, jelly-like growths on the branches in spring and move on to hawthorn and rowan.