Dead Japanese Maples

I have about a dozen Japanese Maples, most of them in pots. I've had them for up to ten years. Suddenly two have died. They were fine last summer & showed no signs of a problem, but when I pruned in January , they were obviously dead & they aren't budding out.

I have two questions:

Can anyone give some ideas as to the cause of their death?

I want to replace one of them. I'll plant one, that's been growing in a pot, in its place in a planter bed - wooden planter that is about 4.5' square. I'm wondering if I need to treat the soil before re-planting? It would be virtually impossible to remove the soil & replace it.

Thanks in advance for any info/ideas.

Liz

Did you see any black marks in the wood when you trimmed them? It could be verticillium wilt if you did. I don't know how common that is in potted plants though. If it is VW, you won't want to plant the trees in the same spot.

Thanks for responding! Some of the branches turned solid black at the ends - ie. the last 5-6". These are really large planter boxes - ie. 4.5' high. One maple remains healthy, at the moment. Would you suggest that I remove it from the planter box?

usually dead tips of branches are black and then turn white/grey.

is the trunk black all through it?

Pictures would help.

Hi, I'm attaching two pics of some of the branches which have turned black.

I assume I need to remove the remaining tree from the planter box? It's about 10 feet from one of the dead ones.

Thanks so much for your help!

just looks like a dead maple - when you remove it saw the trunk in half if it is black inside that would be bad

So, you don't think it's vermiculum wilt? It's just weird that it was totally healthy last summer & fall, but dead as a doornail in January. Thanks again!

You won't really know if it's verticillium wilt until you look at the center of the wood. Like Wha said, if it's black, it probably was VW. If it's not black, it's just a dead tree.

Thank you!