Lace Leaf Maple
We have had this Lace Leaf Maple in the same location for 20 years. It was at least 10 years old when we bought it. After the unusual warm weather in December 2015 and then the blizzard and cold spell in January/February, we noticed the branches turning yellow with spots on them and it only had one-third the leaf growth it normally had. Entire branches turned brittle and died which I tried to prune as much of the dried dead wood as possible. Then, of course, we had the incredible heat in August which seemed to dry up many of the leaves that it had. I've enclosed a few pictures. Thanks for your help.
In general, Japanese maples are subject to many environmental stressors such as drought, poor drainage, too much moisture, temperature extremes, frost damage, too much mulch, planting too deeply, soil compaction, etc. These issues can stress the plant and make them susceptible to disease and insect problems like cankers and root rots.
Make sure the soil drains well or grade the site to ensure good drainage. Look for downspouts dumping water in the area. Japanese maples have a shallow root system. Do not plant too deeply. You should see the flare at the base of the trunk where it joins the root system. Mulch should be no thicker than several inches and keep away from the base of the trunk. Water during dry periods.
Scrape the the stems or bark and look for discolored/brown wood. If you see it, all you can do is prune back to healthy tissue. Once dead wood is pruned, the plant may not be worth keeping. You will have to decide.