Certified GKH Gardening Expert
Unfortunately, your photos did not come through. I am unable to see the damage. There are several things, from borer insects, to fungal and bacterial infections that will cause these symptoms. Unfortunately, whichever it is, there will be a long battle to control it. All of the things that cause symptoms like this are very difficult to control.
This article will help you to get started:
Many thanks for your response.
I attached a photo in response to the email notification but that may not get through. Unfortunately, I cannot find a way to reattach the photo here again.
My ceanothus has a bit strange growing habit. (perhaps due to a bit akwardy cut I was sent online during lockdown) It hugs the ground and just started to grow a bit vertically as well. The plant was otherwise healthy with dark green leaves and light blue flowers. Has developed well in the past 3 years. As the photo shows the browning of the branches and leaves started on the front area where it was hugging the ground very closely. However, the browning does not go all the way back to the stem. There are also some faded green leaves on the very top of the brown branches. There were some rotten leaves beneath the brown branches and I wonder whether those rotten leaves harboured some bacteria that gave rise to disease. I cleaned out the area, of course. Previously, I had a dwarf azalea on that spot and it died, too, after developing some white mildew on its leaves. :(