We have a Japanese Maple in our front yard that has done very well for the last 9 years and all of a sudden it looks like half of the leaves are dead. the soil is a mix of soil and sand and it hasn’t been over watered. Please help! we love this tree and don’t want to lose it! thank you in advance
Thank you for contacting the Toronto Master Gardeners with your question regarding your Japanese Maple.
Unfortunately your Japanese Maple looks like it has a serious disease known as verticulum wilt. It is a fungal born disease, which tends to start by first yellowing or wilting of individual limbs or portions of the canopy often on one side at first (often referred to as “flagging”, and is very indicative of your photograph). This disease usually appears in mid-summer, frequently after periods of hot, dry weather. killing individual branches or section of a tree, before expanding to other sections of the tree.
Infected trees die slowly or suddenly, depending upon the extent of infection and the overall health of the tree. Trees weakened by drought or root damage are thought to be more prone to disease.
There are no chemical controls for this disease of maple once trees are infected. However, efforts to maintain tree health and vigor can help to prolong the life of the tree. . It is helpful to prune affected limbs as soon
as symptoms are evident. Based on how much the disease is already showing, sorry to say that the long term viability is unfortunately not very positive.
Pruning tools should be thoroughly disinfected between cuts with a 10% solution of household bleach or 70%
alcohol. Additional efforts to promote tree vigor by watering, fertilizing (only as necessary, based on a soil test) and avoiding other types of stress are helpful.
Since the fungus is soil-borne, when the time comes to replace the tree, it is necessary to avoid planting susceptible species in the same area.
I am attaching a link for further reading: https://www.thetreecenter.com/maple-tree-diseases/