I trimmed a california lilac in September 16th. I looked at it on Oct 2nd and it seemed okay. Today, Oct 14 all the leaves on one side have turned brown and are falling off. I don't get it. There was a very light frost about six days ago 2 below freezing. Any ideas? A couple other hedges I trimmed have turned brown too?
Leaves on lilacs around here are starting to turn brown at the edges and will be dropping soon. It is mid October after all! I'd doubt it's anything to worry about.
Evergreen ceanothus are pruned right after bloom, cutting mostly near the outside and avoiding old hard stems farther back.
I fought with a ceanothus here for years, seeing large sections turn brown and die back. We were told they are very sensitive to cold arctic winds, which I believe is true, but the damage on our plant often did not seem to relate to those conditions. Eventually the shrub died back to the point we cut it right down...it became obvious then that the culprit was verticillium, which has taken out several other species in this area of the garden, including japanese maples (probably the original source of the pathogen here) and a beloved mountain hemlock. By the way, my ceanothus always suffered from my original error in planting it well below the original soil line...which probably weakened it and allowed the pathogen to take over as much as it did. Lost quite a few shrubs and trees before learning that simple principle of planting...expensive way to learn :-(
