5x 10+ year old dwarf Acers seem to be dying off suddenly
Really hope someone can help. 12 years ago I bought 5 dwarf acers (diff varieties) and moved them from NJ to CA, USA 9 years ago. They have lived happily since then and I moved them to my new house, front porch with morning sun and afternoon shade 3 years ago and they've loved it until this year, when they struggled to full leaf like usual.
One looked dead (Acer1) though I noticed 3 new tiny leaves, near the trunk this week so can't rule it out yet. Two look like they have leaf scorch (Acer 2&3) or have been under watered but the get adequate water. Another came out with some leaves, though I couldn't even see its stem the year before (Acer 5) and then most leaves died off quickly and the last lace leaf (Acer4), again only came out with half its usual leaves and then odd branches keep dying and the branches look black!.
I cleaned my pruners and took off so many black branches but more are dying. There is no stain inside the cut branch or mush so didn't think it was verticillium Wilt but can't think what else it is. The larger broadleaf that looks scorched also has some black starting at its tips.
All are under a large redwood and we do have sudden oak death locally but I am so upset that I can't help these guys. I haven't fertilized but did add a layer of our own composted mulch recently so hope its nothing in there so think they were sick before that.
I did put trays under to catch scarce water as we are in a drought but this is nothing new and have been like it for years. I have just removed the trays though, just in case, as know they hate sitting in water.
I wonder if something contagious is moving from plant to plant. I did get a tip about repotting and getting new compost in there so am going to try to remove a 3rd of the root so that they can stay in their pots in case they are root bound too.