Hello, I'm seeking some advice with a Japanese maple located in the backyard of my property in Southern Ontario (zone 5B), and I'd greatly appreciate any wisdom you can offer. Location, Sun, and Water: The tree is located on a small hill off the eastern corner of my deck. It's positioned on the outskirts of a canopy of large, old trees (sugar maples, oaks, etc) which prevent the Japanese maple from receiving morning sun. The canopy is pretty occlusive (even my hostas were struggling). In the early to mid afternoon, parts of the japanese maple receive direct sun while others are blocked by the lilac to the west or towering sugar maple to the east. I don't think it receives much rain water due to the sugar maple and the fact that its on a hill (redirecting water that does reach its soil). This year we've received lots of rain, and I've been watering it more manually during dry stints. I struggle to imagine how it could have wet feet. Symptoms: Over the past few years, the most eastern branches of the tree (which receive the most cover from the sugar maples) have died off. I'm not sure what type of japanese maple it is (and therefore what color it should be) but I've lived here for 10 years and for as long as I can remember the leaves haven't looked completely healthy. Sections of the tree receiving the most direct sun (on the north-west side of the tree) have bleached leaves with crispy, curled edges which I've assumed is sun scorch. Other areas of the tree have leaves more green in color, misshapen + curling edges, and brown spots. The trunk has some rotten areas (holes) close the soil. I recently cleared the top inch of soil away from the trunk out of concern that eroded soil might have built up over time. The rocks and concrete edging seen in the photos near the base of the trunk have not been there long and won't be staying there. I feel like it may be receiving both too much indirect sun (during early afternoon when it's harshest) and too little (indirect) light overall. Is that off base? Any thoughts on the dark brown spots? Thanks!
Generally health-wise it does not look too bad, some spotting of leaves is to be expected in July when it is hot. And branch dieback of extremely shaded branches is a natural reaction - the tree is not going to spend the resources to maintain a solar panel that is permanently in the shade when those resources could be better spent elsewhere. The hole in the lower trunk is not great, but I have seen far worse on old JM's and it does not appear to be spreading. However, the difference between the two parts of the tree is puzzling. Just to be clear, in the picture copied below, Area A and Area B are definitely part of the same plant? Because they look like two different cultivars. Assuming they are from the same tree they look different, not just in colour but also size of leaves. One possibility is if it is a grafted maple then half of it might be coming from the rootstock rather than the actual cultivar. Please check the areas of the canopy coming from each of the main stems/branches in IMG_4449.JPG and let us know which ones are green coloured, peachy (for want of a better word) coloured, or dead.
@maf My first thought as well when seeing the green foliage. Also looking at the image of the lower trunk (#4449), the branch on the left side could likely be coming up below the graft of the tree and just allowed to grow and become part of the tree. Overall looks fairly healthy with typical growth habits for this time of year.
Thank you both for your replies. @maf, as far as I can tell, it's all part of the same plant. I've annotated a few photos to better show which sections of trunk lead to which sections of foliage. I've labelled the branches leading to the peachy leaves (described by @maf as 'Area A') as "Pink", branches leading to the more greenish leaves (described by @maf as 'Area B') as "Green", and the branches without leaves as "Dead". The "Dead" branches may not actually be dead (I have not scratched them)... perhaps 'leafless' would have been a better annotation... oh well. I've also included the western side of the trunk (closer to the deck / top of hill), which I accidentally omitted from the previous post. It looks worse than the eastern side of the trunk. I'm not sure how large this cultivar is expected to get, but I should also mention that in the 13 years I've lived here, I don't think it's notably changed in size. Could the difference in leaf size between Area A and Area B be partly attributed to differences in sun exposure?
That is weird about the different size/type leaves coming from the same stem but I guess it must be the difference in sun exposure. The lower trunk does look worse than from the other side, but mostly old dieback that is well on the way to healing. Again I have seen a lot worse on old JM's. In image 4470 you can see that "wound wood" has almost closed up the gap - this is the stuff that kind of looks like a lip around the edge. If you can cut off/clean up the area of stumpy dead wood protruding from the gap with a sharp knife or fine saw, without damaging the lip of wound wood, that would be my first step. Then cut off the dead branch, as close as you can to the wound wood without touching it. On image 4449 there looks to be a growth ring on the opposite side of this branch - you want to angle your cut to stay above this ring. If it is not clear what I mean I can draw the cut etc on your photo, let me know. In image 4467 the dead branch on the right has already been covered. The dead branch top centre is clearly dead from the bark colour, and should be cut back as closely as possible without damaging the branch collar. The left dead branch needs a scratch test as you suggested, but again a straightforward cut avoiding the branch collar. Once all the dead is removed it will look a lot nicer and will be easier to monitor health moving forward. Looking at the pictures there is no reason to think it will necessarily decline further. These branches may just have died back as a reaction to becoming heavily shaded by the larger trees you mention. The part of the maple nearest the deck looks like it gets enough light, but without being on site difficult to know for sure.
Just to be sure, you're suggesting I remove the area outlined in pink in IMG_4470 2? Do you suggest also cleaning up the area the yellow arrow is pointing to? If you wouldn't mind annotating Img_4449 with the cut above the growth ring that would great. Thanks again for the assist. Any idea what cultivar this is?
Yes, mainly only the part that is sticking out above the profile of the trunk. Two reasons. First, it is a physical barrier to the wound wood (marked in green below) closing up the gap from a limb that died several years ago. Second, it is in the way of making a clean cut for removing the dead branch above it. Whatever you do, avoid damaging the area marked in green, that is the equivalent of scar tissue trying to close the wound. The "stumpy dead wood" is clearly old and may even be weak enough to break off by grabbing it, but more likely will need a knife or saw. Don't worry too much, just get rid of the worst of it to make it easier for the tree to close off that area - which is a long process that has already been going on for several years and will continue for several more. Yes, it is hard to see what is going on exactly in that area, but if there is material sticking out and creating a barrier to stop the tree covering the area with wound wood, then remove the dead material. See below. Try to aim your cut to come out just above the marked area. Looks like it is a little lower than the cut point on the other side. As far as I can tell from the picture, this is a node that the tree can use to compartmentalise the damage and subsequent infections (like a bulkhead in a submarine, for example). No, afraid not. At minimum would need photo's from early spring, late spring, summer and autumn
