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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.


  • AnniDAnniD Posts: 11,426
    I was searching for something and came across your post which seems to have slipped through the net.
    It's a bit difficult with this being a UK based forum,  but we do have a couple of members in the USA who might be able to help. 
    I hope things haven't got any worse in the last 2 months. 
  • JennyJJennyJ Posts: 8,833
    If they've been in the same pots for several years they are probably root-bound and starved of nutrients. That will have weakened them and made them more prone to any disease that's about.
    It's a while since you posted, so if you did repot them with fresh compost, did it make any difference?
    Doncaster, South Yorkshire. Soil type: sandy, well-drained
  • BijdezeeBijdezee Posts: 1,484
    I agree with what jenny said. Sounds like they're short on water and nutrients.  I've also noticed that they don't seem to like early morning sun, burns the leaves. 

    In the summer and especially when it's hot I have to water mine twice a day. Must be hotter in Cali. 
  • dinkbraddersdinkbradders Posts: 4
    edited September 2020
    Hey there, no they sadly all died once I repotted them.  I am keeping watering occasionally and have taken them out of any trays so the water drains off and have my fingers and toes crossed that they might show some signs of life next year as it happened with one last year that I though was dead that suddenly had one tiny leaf on its bottom stem (has since died though this year).  

    It probably didn't help that they had the same soil but I think they were diseased as the branches kept going black then the leaves dying.  Still very confused as to what disease as they looked fantastic for 4 years in the same spots, same heat, same climate, same sun pattern etc but we do have sudden oak death in the mountains and the property is covered in oak, Laurel, madrone, redwood.

    Thanks though, I just wish I had pics of them when they were healthy but I wont give up just yet and could add a fertilizer with their next watering, just in case they've gone dormant
  • p.s. I'm from Nottingham originally but know how much us Brits love our plants lol

  • If you follow these key rules for potted Acers - this won't happen ... hopefully it's not too late to implement it now:

    1 - It's all about oxygenation of the roots with these plants.  Put them in free draining soil - ideally composted pine bark mixes with some peat free compost and a bit of perlite and ideally a handful of pine bark mini mulch.  This is the mix I use.  Dense, poorly draining, poorly oxygenated soil isn't just bad - it's deadly for them.

    2 - Put them in a pot on the small side and change the soil every 2 years.  They don't like a root-to-soil ratio in favour of soil - particularly water retaining soil.  

    3 - Raise the pots up on pot feet - so the water runs out of the bottom when you water.  Make extra holes if necessary.  Don't put stones at the bottom as the transfer of moisture from a very fine mixture to coarse material is actually slower than straight out of free draining compost into the holes.  

    4 - Water regularly.   So every day or other day - ideally at the same time (morning) - and just enough to keep things damp, not soggy.  Keep this up during all weather - particularly strong windy periods.

    If you follow all of the above - put them in a good aspect (morning sun if poss) - all the leaf crisping in summer and slow decline will go away, I promise you :-)
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