The scion (the graft) has died but the understock lives on.

Al

I live in Michigan zone 5b. I have lost two established Japanese maples (Bloodgood) under similar circumstances. Both were 10 years old and well established.

I first noticed trouble in the fall when some of the leaves shriveled up but did not drop, they remained on the trees throughout the winter. Then the following spring major sections of the tree did not leaf out (same sections that had the shriveled leaves), other branches however did leaf out. The following year both were almost completely dead.

I suspect some type of virus or soil pathogen but nobody seems to have any solid information. Now I am hesitant to grow Japanese maples.

Al-
even though the top is still not brittle? what would cause it? And can i basically trim the top and let the bottom part grow out, or is the tree pretty much doomed?

I am no expert but I suspect that the tree is pretty much toast. You might wait a couple of months and if there is no sign of life on the top lop it off and see what develops. Obviously the tree will be odd looking, but you have nothing to lose.

I thought I could save mine, and they did exhibit some growth after the first episode, but the following year they continued to deteriorate so rather than having ugly half dead trees in my garden I got rid of them.

If you want to keep the tree, pick a vigorous shoot high on the understock to keep. Pinch the center out of ALL the other shoots to slow them down. The plant will channel most of it's energy into the unchecked shoot you selected. Then, start to remove the lower shoots, starting with those immediately below the shoot you selected. Make sure you don't allow a bunch of adventitious beds to grow from the base of the shoots you severed - just rub them off regularly. Time the removal of the lower shoots so they are all removed by about Father's Day next year.

Al

Different situations between achilleas post and Brians :-) As Al indicates, achilleas is an indication of graft failure, not a necessarily uncommon situation with JM's, depending on grower. I would certainly consider keeping the tree (after removing the dead top growth). And following Al's instructions....unless you wish to grow your tree as a shrub, in which case you can just leave it be.

Brian, your description sounds very much like one of the fungal pathogens that can affect JM's. Unfortunately, unlike a graft failure, they tend much more likely to be fatal, often in the same season but surely within one or two growing seasons. And your instincts may be right on as far as avoiding JM's in that area -- with several of the pathogens, replanting in the affected area will just continue the problem. It is best to select a more disease resistant species.

thanks for the follow up Al and gardengal! i'll see what i can do. Hopefully your advise will work.