Dwarf Japanese Acers dying

[rvf4uk]

Really hope someone can help. 12 years ago I bought 5 dwarf acers and moved them from NJ to CA 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.

It is 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 already been in pots and trays. I have just removed the trays just in case as know they hate sitting in water.

Anyone had a similar situation? I wonder if something contagious is moving from plant to plant. I can't even find pics of when they were in full health sadly

 

[0soyoung]

It appears to be root problems, IMHO --> root anoxia to be specific.

It looks like you are using an organic media/soil - when was the last time you repotted them, largely removing and replacing the existing potting mix? Organic media breaks down over time and reduces the air filled porosity --> root don't get oxygen, don't do their job, and die over time.

This circumstance also means and increased sensitivity to 'overwatering'. You say nothing about slower drainage, but this would also be a symptom/cause. People in rainy winter climates often suffer this kind of problem.

 

[rvf4uk]

Thanks so much for the reply.

Blimey I haven't repotted them in 9 years!!! just added mulch around the top. I just took out one of the acers from its pot and it was pretty solid with roots all the around the soil but not particularly root bound, I'm finding it difficult to knock any of the old media away. If I wanted to pot it in the same pot would I just trim the roots back a bit and add new media around the existing? (the pot is a good size for the patio and with Covid I can't get out to the store) Also a bit worried it would be a huge shock for it whilst its sickly but think you are right and needs to be done pronto!

My other two pots are upright greek urns and I am stuggling to get the acers out as the top is thinner than the middle part - oops

 

[0soyoung]

I keep a few as patio trees too. I use a keyhole saw to cut around the inside perimeter of the pot. With largish trees, I just dig out the soil and root ends/bits letting the heavy root 'ball' stay in place. I replace it with medium landscape bark and no more than an equal volume of soil (sometimes the stuff I dug out, less the root debris). The keyhole saw trick (or something similar) ought to allow you to get it out of the pot.

This is a challenging time of year to be repotting maples. The leaves easily desiccate, so they must be in shade and occasionally sprinkled through the day, especially during the heat of the afternoon when the relative humidity is inherently low(er). Defoliation is not an option because the leaves are required to power the root regrowth needed to recover from repotting damage. Just effectively reducing the size of the existing soil plug and back filling with fresh soil shouldn't be too challenging.

On the other hand, it is 'routine' to bare root maples in the spring 'as buds swell'.

btw, the bark mix is good for 3 to 5 years - just add some general purpose fertilizer in the first year unless you have bark that has been composted for a year instead of 'fresh' bark. Some 'fresh' compost/potting-soil would buy time to next spring, I think.

 

[LanceMac10]

Japanese Maples need a period of cold winter dormancy. Providing "winter" in NJ is easy...CA...? Not so much. More so when containerized.

 

[sorce]

Welcome to Crazy!

Last winter sucked balls.

Sorce

 

[ajm55555]

Japanese Maples need a period of cold winter dormancy. Providing "winter" in NJ is easy...CA...? Not so much. More so when containerized.

Yes @LanceMac10, but they lived happily for 9 years now in CA. I think it's more of a soil issue like @0soyoung is saying.

 

[LanceMac10]

"Happily for nine years" Some people's "happy" is other's "downwards spiral".

 

[ajm55555]

"Happily for nine years" Some people's "happy" is other's "downwards spiral".

If you think it's the climate, for sure you know better than me. I've never lived in California ;-) And probably it also depends on where in Cali...

 

[LanceMac10]

If you think it's the climate, for sure you know better than me. I've never lived in California ;-) And probably it also depends on where in Cali...

My response was to the original post. Did not see they have not been repotted for those nine years, just added more mulch......head scratcher.

Don't think I know better better than anybody but these trees look pretty thin and under-developed for having twelve years of care.

 

[0soyoung]

USDA zones in California range from 4b to 11a.
New Jersey, from 5b to 7b.

 

[BonjourBonsai]

Last winter sucked balls.

In so many non-bonsai ways too!

 

[fredman]

I have a few big trees in similar sized pots. They've been in there for about 4 years. Mid spring last year I noticed them not growing well. Same thing...the soil was compacted....water couldn't penetrate anymore.To late to replant. I took a garden fork and forced a number of holes in each pot. That created some airation and made some space for roots to expand. It bought some time for them to grow. They need to all come out this spring and get fresh soil.
Not sure about your climate or season, but you might still be able to take them out. Remove 25% of the bottom layer and maybe an inch or so around the rootball. Backfill with some ericacious pot soil. Also make some holes for water to get to the centre of the rootball.
Next spring when the buds swell remove more and they'll thank you for it...

 

[Mikecheck123]

Japanese Maples need a period of cold winter dormancy. Providing "winter" in NJ is easy...CA...? Not so much. More so when containerized.

The Bay Area has zillions of maples that all go dormant just fine, even though it rarely dips below 40F.

Not sure where OP is, though.

 

[Forsoothe!]

OP needs to go upper right hand corner and click on his Icon and enter a location so advice can be tailored to specific climate. Bakersfield and Truckee are both in California.