Moved in last year and nursed a Japanese maple back to health and now the leaves are drying and curling up at the ends. Reason?
We have had an unusually hot, dry several weeks this summer (it is now July 30 2018). The most likely cause of your Japanese maple’s leaf problems is leaf scorch, which usually occurs after relatively long periods of dry, windy weather or very sunny weather. In these conditions, the tree may be unable to supply water fast enough to the leaves, which lose water by transpiration. This problem is compounded by other factors that can interfere with the tree’s water uptake, e.g., where the tree is planted in an exposed site, or in sandy soil/gravel (which is unable to retain water), or is infested with insects/pests.
The tree should be planted in well-drained soil with lots of organic matter, and watered thoroughly at least once a week. Watering should continue until the late autumn. Next spring, fertilize the tree.
For more information, see our Ask a Master Gardener Site. Brown curling leaves on Japanese Maple.
You did not provide details, but a fungal disease called verticillium wilt could also cause leaf scorch, although is a less likely culprit. See Connecticut Agricultural Experiment Station. Verticillium wilt of ornamental trees and shrubs.