Red leaf Japanese maples struggling

[AdamBonz]

This year nearly all of my red leafed Japanese maple seedlings, both broad and lace leaf varieties have declined and maybe died. I don't know if its due to Melbourne weather or over watering or something else. The trunks look deadish - dark but these red maples tend have a darker trunk. I took these photos after cutting all the dead leaves off last week, but I guess that's also a bad sign, having the leaves die stuck on the plant. The leaves and stems were limp and crispy or blackened. I'm thinking root rot, but just surprised that my dozens of my green maple varieties are going super gang-busters right now and my red maples are inching toward the bin.

Repot too late?
Any advice?

Thanks.

[TimS]

I learned the hard way germinating hundreds of lace leaf by seed that 99.999999% tend to die off by the 2nd year, just don't want to live. Regular green maples do just fine by seed, but certainly lace leaf want to exit the mortal coil ASAP

[Kedron Brook]

Use Google to find TinyPanda. This webservice shrinks the pictures and then they can be uploaded here. Everyone likes pictures

[shibui]

Weeping JM are notoriously difficult to keep alive unless grafted but red leaf types should not be much more difficult than the green ones.
Any other possible differences in culture? Like are the red ones in one area and greens in another in your yard? Different pots, soil type? Are some older than others? Been in the pots longer?

Check the base of the trunks for black bark. That's one problem I have experienced with JM but not only red types. If the bark is turning black and new shoots wilting, leaves collapse and turn black there's little hope.

If they have just dried out there's every chance they will shoot again.

[Trimmy]

The black bark means it's rot. I had the same problem with two of mine even though they were treated the same as other maples that seem fine. I wish I had an explanation for it.

[Dean]

Normal green Japanese maples are genetically stronger than dissectum and purple seedlings.My advice for these types don't overpot, don't over water however I have noticed they don't like radical changes in temperature once they get over three years old they are ok,but we'll drained potting mix is essential.

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