Leaf Scorch On Japanese Maples

There are a couple possible reasons that can cause these symptoms and sometimes such damage can be caused by a combination of these.
1) Some maples do not tolerate sudden heat. The most sensitive to scorch are the cut-leaf Japanese maples. The trees just prefer cooler temps and more humidity. Wind makes it worse.
2) Fertilizer burn. If a plant is fertilized by too-strong synthetic fertilizer, it can cause scorched edges. Sometimes the fertilizer is from an application to a nearby lawn.
3) Drift of water on leaves frequently. If foliage is hit with water daily, or every other day, especially at night or very early in the morning so that the leaves are wet at the coolest part of the day, it can cause fungal issues that resemble or add to leaf scorch. Note that if a sprinkler system is going off for fifteen or twenty minutes either daily or every other day that is not nearly enough to adaquately water a tree. Water deeply less often to be sure that more than the surface of the soil is being watered. Many times irrigation systems are set up to irritate, not irrigate plants!