I have a Goldrush metasequoia. It is several years old now. This year it seems to have developed some wilt that is killing off the new growth. Any idea what the problem is and what I can do about it? Here is some of the background info. I'm in Orillia Ontario, zone 4-5. I don't know when this problem started because I was away from July last year to January this year, so it could have started last fall though I have no reason to think it started any earlier than this spring. However, a lot of plants have had dieback over the winter. I was told there was a coldspell in December and we had a bit of thaw and freeze in the late winter. This might account for the lack of new growth at the top of the tree, but that isn't really my concern. My concern is that the new growth that the tree has put on this spring is now wilting and dying back. This winter I top-dressed the tree with llama manure and possibly some sheep manure mixed in. I don't know if this has burnt the tree. I did, however, top dress with the same the previous winter with no problems at all. Finally, this is the Goldrush variety, so the light green-yellowy colour to the needles is appropriate (I've included one photo with the cornus in the background to give a sense of what the needles should look like). It's the wilt and dieback that I'm concerned with, not the colour. Anyone have any suggestions what to do? Is the tree doomed? Thanks, Larry
These are usually bulletproof. I'd be concerned about redwood canker: Dawn Redwood Diseases @Michael F might be able to diagnose this, if he's around to chime in.
That canker is a new one to me. Worth adding though, that zone 4 is decidedly outside of Metasequoia's 'comfort zone', it prefers zones 6-9. So it may just be cold-related damage.
thanks for the replies. Yes, initially I thought it was cold damage, but the die-back is in stages -- a branch is perfectly fine, then it starts wilting and dies in a week or less. Once it is dead another branch starts wilting and dies, and so on. If it were cold damage, presumably the problem would show itself from the beginning and wouldn't happen in bits and pieces, would it not? I had also thought recently that the problem was a nearby black walnut, but was advised that walnut toxicity wouldn't express itself that way either -- the staged, localized die-back, that it would be uniform wilting and die-back. This is from a plantsman at the Royal Botanical Gardens. He suggested root girdling under the assumption that it was a recent transplant. But the tree was planted on the site 4-5 years ago and is about 10+ feet tall now (before the dieback). I do think that there was some winter cold die-back. A lot of the tree never leaved out in the first place. My concern is more with those branches that did leave out in the end. They seemed healthy, but now they are wilting and dying back. I'm concerned I'm going to lose the whole tree.
Winter cold damage on deciduous trees can actually have some odd effects - the cold may kill the cambium beneath the bark, but leave the buds unaffected. The result is that the tree leafs out as normal, but then some time later, the leaves run out of water as the dead cambium can no longer transport water and nutrients up from the roots. I remember seeing a large Nothofagus obliqua (a not-too-hardy Chilean tree) die suddenly in the June following a severe winter - it was in leaf and green one day, then a week or two later it was shrivelled up and yellow-brown. Why yours should die off in sectors is more difficult to explain, but perhaps the cambium kill has only been partial, and that some water can get through, but not enough as the weather gets hotter. Worth looking for new sprouts near the base of the tree, Metasequoia can coppice when it is young.
