After the most severe winter I can remember, a number of my maples are leafing out with much smaller leaves than normal The problem is that, in the past when this has happened, it has been a sign that the tree is under stress, and, sure enough it has died the next year This year I can see the end of a 15 year old Asahi Zuru (looking decidedly pitiful), two Garnet (one about 20 years old and the other, a high grafted one of about 10 years) a Shin deshojo that I have had for about 5 years, and a Kinran Anybody else having a similar experience? Any words of wisdom?
Not exactly words of wisdom, but I suspect reduced root mass as the cause for the small leaves. I have seen similar small leaf behaviour in two year old containerised seedlings which later turned out to have had their roots eaten by vine weevils (or similar root weevils). If this turns out to be the case, then the question is what caused the root decimation? Vine weevils won't check a plant in the ground. The temperatures in Northern Ireland by themselves are not low enough to damage Acer palmatum roots in the ground. Is there a chance they could have been waterlogged in the late winter or early spring when the water table is higher than normal? These plants are adapted for growing on hillsides in free draining volcanic soil in a climate where most of the precipitation is during the months of June to September. Any saturation of the ground during the early months of the year is likely to lead to major root death and subsequent invasion by secondary fungal and bacterial infections. You may have considered these possibilities already, but I thought they were worth mentioning again. Good luck with these maples.
There are a lot of factors that can lead to a palmatum type Maple yielding smaller leaves than normal. Environmental stress, stress due to pathogens, stress due to nutrient deficiencies (Zinc and Magnesium deficiency can cause “little leaf“. Copper, Calcium and heavy metal toxicity can also cause little leaf) and sometimes stress due to overfertilization and even stress due to the wrong chemical constituent and/or formulation of a fertilizer, can all cause leaves to become small. To better identify what have caused the leaves to become smaller in size due to stress we may have to see some photos of the Maples in question. Generally better to see photos of the plant prior to showing signs of the stress, photos of the tree under duress and photos of the tree after its demise. It is not an easy thing to do to post photos of a tree we've had for 20 plus years or more and later on lost it. I know for me I have to accept blame for what happened to the Maple even when the plants decline may not have been solely my fault. I always think in terms of what I could have done to help matters, help prolong the life of the Maple, even when knowing that the end of the plant might have been near no matter what I did. A case in point is the boxed Iijima sunago I posted a photo of in the "Bark" thread showing the remnant diseased wood of the right fork of the tree that was decimated into nothingness in three years time from its bout with Tight Bark and Verticillium alboatrum. What is not shown is that the left fork of the tree lived for another ten years before it succumbed in the same fashion. When we buy a tree that is fifteen years old to start with, have it for another 20 years and then see it decline in three to ten years like a metastasis cancer, we lose a lot of faith in these plants that we may have them for 40 and 50 years or be able to pass them along to our grandchildren and beyond. Much of the time our initial feeling that these trees can live for 50 years and more is being unrealistic. Some varieties of palmatum type Maples have had a history of only being alive for people for roughly 15-18 years anyway. Some varieties of dissectums may have only had a life span for 7 years and less for several years. Two of them were the old Filigree and Silver Lace, no matter if they were on their own roots or came about from seedling selection. After years of selective grafting we were able to induce more vigor into the plant, lessened the amount of Verticillium alboatrum in those plants and felt that an average Maple could live for 15 years and more for most people. Having this notion that these Maples could live that long for some people was a major accomplishment for the nurserymen that spent a lot of time working on those two Maples in order to perpetuate them long enough to sustain a viable source of wood for propagation over time. No doubt a lot of Maples died out like the old form ribbon leafs because we failed to graft them at a time when we could have helped prolong their longevity. We lost out because some of us felt that these Maples were destined to have short term lives and just accepted that we would not have them long as collection plants. There was not even a belief that someday these trees could become a viable landscape plant for people and if they could not live for any length of time in a landscape they were not considered to be a worthwhile project to even propagate in a nursery for resale. Nothing has changed in the last 50 years or so in the nursery industry, if you buy a plant and lose it in one to three years time you will be hesitant to buy another plant again from that same nursery. It is unfair to those nurseries offering Maples that are known not to live long for people but at the same time we all are hoping that some of them will live a long time for someone. It is seeing that one Asahi zuru and Garnet live for 40 years that keeps the purist and professional nurserymen motivated and “remain in the game“. Off-topic: off on a tangent again below. A quick comment about whether to water or not during freezing soil temperatures. Depending on our soil substrate, soil mix if you will, I want moisture in the root zone, even when the root balls are frozen solid. We tend to forget that the water mold fungi are held in check in freezing temperatures. We may see some symptoms of the water molds in a thawing out for in ground and container plants. If given a choice of having a root system become decimated or severely freeze burned over a long period of time or having a tree be subjected to a water mold fungus, I'll deal with the fungus any day of the week. Yes, there are some soil drenches that can help for the fungus but at the same time we have to be careful that we don't harm the root systems ourselves in our tree protective maintenance. Much of the time we kill off root systems by not knowing when and when not to apply a fungicidal soil drench. An insecticidal soil drench for the root weevil may be necessary in areas that are prone to have significant infestations but even then an application during the Fall and Winter months in most areas is not recommended. Spring applications when the roots are functioning is probably the best time of year for a soil drench application, in areas where it is felt to be necessary but in most Maple growing areas it is not going to be required and not even needed at all. It is wishful thinking that a Copper based fungicide will help for quick decline - Verticillium dahliae but a soil drench for Verticillium alboatrum and in regions that are known to be susceptible to the many forms of Pseudomonas syringae, can help protect the plant, at the expense of some root system development. (Even here the Cooperative Extension will recommend using a Copper based fungicide as a soil fumigant for in ground nursery trees, not to suppress the bacterium but act as a preventative to limit the spread of the bacterium from infected trees to non infected trees only). Jim
Thanks for the comments My own idea is that there must be some root problem, brought on by environmental stress. I hardly ever fertilise (maybe I should?) because I seldom grow my maples in pots. Gardening here in heavy undraining clay can cause problems, but it is unusual to see such a mature tree suffer. It and now a 'A P Taylor' has the leaves drying up and dying. The latter tree was just bought last year and planted high in the ground to help with drainage. We have had little or no sun but plenty of winds at times and loads of rain All in all it hasn't been a good period for my trees
The strange thing here is that the two Garnets are recovering, but Oridono Nishiki has joined the 'dying' plants, which are now all variegated varieties ... Asahi Zuru, Oridono Nishiki and Taylor I am ''''''baffled''''''''