Sorry Joe.I’ve now realized, all too late, my pattern of failure with this species. Initially they grow vigorously for a season or two with no problems. They are then ready for a cutback, and following this they never fully recover, slowly weakening and dying from /anthracrose/. A healthy maple should have no problem recovering from cutbacks like that. Really a shame, this tree had come a long way already and had some real potential. Now the question remains, how can I prevent this same outcome from occurring in the future?
I have certainly found this year an ounce of prevention is worth a pound of cure with these issues. Previously I had foregone all the preemptive preventative treatments, thinking they were unnecessary, however it’s quite clear to me now that it is a necessary evil. I have read countless articles, especially the ones by MarkyScott, and I’m now trying to form a set plan. I’ve already power washed all my benches, removed all the leaves I could especially any maple leaves from the pots, benches, and gravel around the benches, and as soon as my bulk Lime Sulfur arrives I’ll be spraying that. Following that two weeks later I have a horticultural oil spray I’ll use.from what i understand, the density of the kotohime leaves increases dampness/humidity, and decreases air flow = increase chance of issues/disease.
1 - my kotohime are as dense as the one you posted above (attached here, for clarity's sake). The internodes are unnecessarily short, so i removed a leaf from most leaf-pairs, alternating sides. some people do this to allow light to to the interior of the tree, or to limit branch thickening - i did it to play it safe with my kotohime in terms of disease, since they are all too close to my precious deshojos on the bench!
2 - a few members have gone out of their to explain the importance of spraying trees at bud swell, and have documented the process very clearly. the link below is a good place to start. you can also use the search function and try words like 'fungus' and 'sulphur' etc and add by @markyscott to your search criteria. Get out your notebook and make 3-4 hours of space in your schedule
2 paragraphs deserve special mention:
"The fungus overwinters on buds, bark, twigs, fruit, fallen leaves or petioles depending on which hosts and pathogens are involved. It attacks leaves in spring when the cool wet conditions are optimal for its growth. The disease cycle begins when spores are dispersed short distances by water or spread long distances by air to newly forming shoots. The fungus becomes active about the same time that the tree does."
"Preventative chemical sprays should be applied just before bud break every spring. I use a diluted lime sulfur solution (5 oz per gallon) on all deciduous trees just before bud break every year."
if i was a fungus, i'd be hide-and-go-seek champion of the world if my playground were the bud-dense branches of kotohime, and boy does the volume of those buds over such a short area ever provide the opportunity for penetration too!
Im in Montreal, and have a south-facing yard. All of my maples get direct sun from sunrise until about noon. After which they are in the shade. This is not ideal, but it works. I mention that I am in Montreal because I used to live in North Carolina, and I can say with confidence that my direct sun now is not like your direct sun.Do you keep your koto in full sun?
Yep they’re all outside, currently on a raised platform under this bench with a tarp over it on the colder nights, only 2 times so far.If you are overwintering your trees outdoors, you are lucky. Mine are indoors for winter. I am still trying to figure out the best situation for applying lime-sulphur to my trees before bud break, since they will be indoor at that time, and outdoors it will likely still be below 0C (32F) at that time. I might have to wait for a warm day, bring them out, spray them, and bring them back in before nightfall. FML.
Im in Montreal, and have a south-facing yard. All of my maples get direct sun from sunrise until about noon. After which they are in the shade. This is not ideal, but it works. I mention that I am in Montreal because I used to live in North Carolina, and I can say with confidence that my direct sun now is not like your direct sun.
Comparative information may be more helpful for you. In my experience, deshojo and kotohime are more sensitive to sun, in comparison to my kashima and arakawa. but I don't know if these are general rules, or particular to my situation and specimens.
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