Red JM lost all foliage over summer - too late?

[zeejet]

I live in coastal San Diego where many deciduous species like Japanese maple are almost impossible to grow. Of course, as a beginner, I didn't know any better when purchasing a JM this January.

For full context:

• It came from Brussels' Bonsai in Missouri
• I was watering with very hard water and giving full sun from January until June. After that I started using 40% shadecloth and RO water.
• It's a generic red maple seedling
• It's been fertilized with mild dose of Osmocote Plus
• My two other juvenile JM's are doing fine (Mikawa seedling and a grafted Summer Gold) but I received those AFTER I had put up shade cloth and switched to RO water.

It flushed out beautifully in March and was healthy through early May.


By mid May, there were minor signs of leaf scorch and by June, it was starting to look pretty bad.
Currently, there are virtually no leaves left (only a few buds that popped but never grew out fully) and there is still another 2 months of growing season here in San Diego (our temps stay in the 70-80F range during the day until late November).



Are there any possible solutions to this? The move to shadecloth and RO water did nothing to slow the decline. I feel like it has little to chance of creating and storing enough energy for next season.

 

[Mike Westervelt]

The twigs and buds look fine, did it get dried out briefly? If so it will probably be fine just be careful not overwater until it starts pushing new growth.

 

[zeejet]

The twigs and buds look fine, did it get dried out briefly? If so it will probably be fine just be careful not overwater until it starts pushing new growth.

It's very much alive (a LOT of healthy but dormant buds) and the current soil is pretty dense and stays wet for a while. Even in summer, it's moist for 2 whole days before needing water. It's far too risky to repot it to better soil right now.

 

[rockm]

I live in coastal San Diego where many deciduous species like Japanese maple are almost impossible to grow. Of course, as a beginner, I didn't know any better when purchasing a JM this January.

For full context:

• It came from Brussels' Bonsai in Missouri
• I was watering with very hard water and giving full sun from January until June. After that I started using 40% shadecloth and RO water.
• It's a generic red maple seedling
• It's been fertilized with mild dose of Osmocote Plus
• My two other juvenile JM's are doing fine (Mikawa seedling and a grafted Summer Gold) but I received those AFTER I had put up shade cloth and switched to RO water.

It flushed out beautifully in March and was healthy through early May.
View attachment 562468

By mid May, there were minor signs of leaf scorch and by June, it was starting to look pretty bad.
Currently, there are virtually no leaves left (only a few buds that popped but never grew out fully) and there is still another 2 months of growing season here in San Diego (our temps stay in the 70-80F range during the day until late November).

View attachment 562470

Are there any possible solutions to this? The move to shadecloth and RO water did nothing to slow the decline. I feel like it has little to chance of creating and storing enough energy for next season.

Tree is alive. I'd allow it three hours of morning sun, then shade in the afternoon, IF your yard allows that siting.

I'd expect it to leaf out again in a couple of weeks. Defoliation on JM's from some kind of trauma isn't a disaster (if it happens only once in a season). Some of my maples have lost all their foliage because of some kind of fungal thing. They dropped all their leaves by the end of Aug. a few years ago. They pushed new leaves the following spring with no issues.