Q.Shrivelled leaves on Cornus from summer through to Autumn
I have a small garden Cornus 5ftx 3 ft , had for 5 years . It over winters well and is beautiful in spring / early summer , as summer progresses the leaves shrivel up and remain on tree , very unsightly . Only one or two turn red before they fall in autumn.
We live north east Scotland on the Morayfirth Coast , Our garden is south facing ,soil neutral , I put bonmeal on in Autumn and a general feed spring time .i do water it if low rainfall .
Hope you can help as I love this little tree
I suspect - BLS "bacterial leaf scorch". Although with your location, it could be a leaf scorch related to extreme environmental factors, wind, salt.
Bacterial leaf scorch is a plant disease that is spread by an insect pest, and then the bacteria invade the internal conductive tissue and interfere with uptake of water and nutrients. So the effect is the same type of drying of leaf tissue that occurs if there was a water deficit. This water deficit is not related to actual drought or lack of soil moisture, but due to blocking of water conducting vessels in the tree.
Because of the type of infection and the location of the causal pathogen, there is no good treatment that can assure a cure. There is antibiotic treatment available by stem injection, but that needs to be applied by a professional with specialized equipment. And then it has to be applied annually, and is only for suppression and delaying the advance of the disease, not for complete cure.
Environmental leaf scorch is due to drought stress or wind and salt drying of the leaf tissue.
https://www.rhs.org.uk/advice/profile?pid=345
https://www.rhs.org.uk/advice/profile?PID=263
https://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/BacterialLeafScorch.aspx
