Over the last 5 years I have planted 3 different Autumn Flame Maples. The oldest has already died and the next oldest is currently dying in the same fashion. It seems that they start to die about the 3 year mark. It starts with the leaves being much smaller than normal and growing in clusters. The tips of the branches start turning black. Any ideas what is happening to my trees and how to cure them?
@DAB good afternoon and welcome to the forum. First of all did you plant the Autumn flame replacements in the same place as the old ones that died? My concern is that you may have Verticullum in the soil, this can stay there for many years, so any new maple you plant will also succumb to this. Blackening of stems is a sure sign of Verticullum and your new tree will I'm afraid most probably die, if this is seen to be the cause. The other alternative to VW is over watering, this can cause leaves to be smaller, as they are unable to receive proper nutrients and water to the upper branches. Have you had a lot of rainfall in your area? What type of soil are you on ? Maples do need a very free draining substrate. They do very badly if sat in water. This will cause root rot and eventually kill your tree. To test your tree for Verticullum wilt, cut a branch and look at the cross section. If you see black rings then your tree does have Verticullum wilt. If you see these rings then IMO you need to replace with a shrub or tree that is resistant to this soil borne fungal disease But a maple 'NO'. There is no known treatment or cure for Verticullum, 'at the moment that is'. Others may have a different opinion, but these two options is what I feel you are possibly looking at. I have attached a link so that it will help you ID Verticullum wilt Verticillium wilt Just a footnote, I believe your soil maybe on the Alkaline side. Maples do better in neutral to acidic soils. A test to check is probably a good idea.
Like @Acerholic, I think it's a fungal (or perhaps bacterial) disease, maybe Verticillum, but it's always hard to make a proper diagnosis. The quality of the soil may also have some impact on the health of the tree. Like the above-mentioned gentleman said, if the soil is too alkaline, this will cause chlorosis, a lack of essential elements like magnesium, etc. The tree being weakened, it's more prone to pests and diseases. Anyway, it is recommended not to plant a tree of the same species where one died, all the more if it's the 3rd one in the same spot. Try spraying it with a copper-based spray, or sulfur, or both (Bordeaux mix) now. After leaf fall, renew it, and burn the dead leaves.
Thank you both for your quick response. I live in Denver and we are currently in a drought. The tree that is dying and the one that died are in two different parts of the yard. The one that is currently dying replaced a crabapple that had blight. The crabapple used to be surrounded by creeping Junipers so I would think the soil would be more acidic but I will definitely get a test. I cut cross section and attached it. It looks fine to me but it may be to early for a newbie like me to tell. I've used ground clear to spot treat weeds in the past but no closer than 8 to 10 feet from the base of the tree so I wouldn't think that would cause an issue. To be safe when I noticed the leaves I got some Biogize SD Soil Detox. to treat a 5' section around the base of the tree.
I just did a soil test. pH is about 8 and alkalinity is about 180 so the soil is definitely too alkaline. Is there an ideal alkalinity and pH for Maples?
@DAB, the cross section does not point to Verticullum Wilt. That's the good news. But the PH points towards alkaline soil. Maple trees do not grow well in very alkaline soil with a pH over 7.3. The alkalinity of the soil inhibits the uptake of nutrients by the trees roots, which also causes iron chlorosis. In the wild, maple trees are found in soil with a pH range of 5.5 to 7.3. So IMO, your soil will not cope with a Japanese maple at a PH of 8. It will sadly be time to make a decision on a possible new tree for your garden that is tolerant of higher alkaline soil. But if you want to grow a lovely Japanese maple, how about a potted tree. Many people are in the same position as you, so they plant their trees in pots. Here you can regulate the soil properly. I would not go down the route of trying to amend the soil to lower the PH. You will be fighting a losing battle IMO. Sorry I cannot give you any better news, but please do think about the latter option.
@Acerholic Thank you very much for the information. You can't fight mother nature! :) I'm glad I know so I don't want anymore money on a trees that won't work for my soil type.
Right, and that's good news for you. I also have very alkaline soil, and water : I regularly use hot white vinegar so the taps can keep running. All my maples are potted (except two or three). Thus, I can manage things much better.
