Hi all. So I was having a look at some of my maples yesterday and noticed 2 in particular looking rather unhappy. My Nicholsonii looks like it has suffered a pretty hard frost as all the buds which were swollen and about to emerge are now droopy and falling off. I'm hoping they'll drop off and it'll have enough energy to push some new buds. I'll take a picture of that one later. The main concern I have is for my Elegans. It appears it could be frost damage that has expanded the cambium layer or something. Or perhaps is a bacterial infection that's spreading upwards. I only looked at it a couple of weeks back and didn't notice it, so a frost would make sense for the extent of the damage to show so fast. The buds all look fine though.
Ouch, doesn't look too hopeful. I've seen similar flaking dry bark in the spring before, and my pet theory is that the cambium has been dead for a long time, but hidden by the bark. Eventually the bark dries out enough that it starts to flake off revealing the damage that has been there for a while. The blackened areas don't look too good either, whether that is the primary cause or secondary infection, I could not say. When it has happened to a tree of mine before I have wondered if drought stress or sunburn from the previous summer could have killed or damaged the cambium, but was not apparent till the following spring. Sorry, no concrete answers just things to consider! If the top of the tree turns out to be completely dead you might be able to salvage something by cutting back to healthy scion wood below the damage (if there is any) and letting it shoot from dormant buds. Also, do you treat for vine weevils grubs as the symptoms on your Nicholsonii would match those of a vine weevil winter feast?
Thanks, I might send some pictures to the garden centre as they do offer a 1 year sort of health guarantee and I've bought so much stuff in there the last few years, they know me very well! I've had 2 other maples I bought from them fail due to pseudomonas and they let me swap them out no problem. I guess it's whether or not they think it's a bacterial issue or just a weather condition related failure in which case I don't really expect them to give me credit. Sadly the black/grey area starts below the graft area so not really any point cutting back from there, it's probably a goner. I occasionally do a vine weevil treatment but haven't for a while, they mostly seem to go for the heuchera I have all round the garden and not so much the maples thankfully! I'll get some treatment and give them all a dose to be on the safe side. I'll check the soil then take a picture of the Nicholsonii later and report back.
Ok so I didn't notice the Nicholsonii also has the exact same thing happening on the trunk and working its way up. I think I may just bin them both and try to find replacements. Annoyingly the garden centre didn't have either of these cultivars last week and when I bought them it was the first time I'd seen them for sale there and haven't since! The soil looks fine, roots look fine and no sign of any weevil larvae.
Did you buy them after the heatwave or before? If afterwards, my guess is the stems were cooked at the nursery, with the true damage only now becoming apparent, and added to by secondary infections. I base this theory on a couple of occasions where circumstances have dictated I could not maintain an adequate watering schedule during the hottest part of the summer, and the next spring I have lost maples that were in the sunniest spot with very similar damage to what you are showing. Only a theory, but it fits with my experience. More than willing to hear a better explanation from people with more experience....
Looking at my posts in the forums and pictures I have on my phone, I think I bought Elegans around August-September time roughly, so after the heatwave I think. Once I had it at home it stayed in semi-shade and then I tucked it into a corner with others still in pots to keep the worst of the winter wind off of it. I bought the Nicholsonii at the end of June. It got a lot more sun during the summer and then exposure during winter. According to one of my previous posts the garden centre do actually usually have Nicholsonii, which is strange because I don't think I've seen any since I bought mine!
So assuming these 2 have had it. I now have 2 positions in the garden I had intended to put these... Both full sun positions, one I was going to keep the Elegans pruned into a slightly more upright form and the other allow the Nicholsonii to spread a little more. Elegans is next to a fence but more open position although very loosely between two fruit trees which will eventually provide some midday dappled shade, Nicholsonii was going next to a Twombly's red sentinel and an Anne Irene in probably the hottest part of the garden. Anyone have any suggestions for replacements if I can't get hold of the same cultivars again? I already have the following which might be suited if they'll handle full sun all day? Looking for a nice contrast in either colour/form/leaf shape. Villa Taranto Koto No Ito Ichigyoji Beni Shichihenge Oregon Sunset Ryusen