Pruning a Japanese maple
I'll answer the easy question first. Japanese Maples can be trimmed summer, fall, or winter. Avoid Spring since the sap is running high and would likely invite insects to cause damage to the open wounds. Now for the how to prune properly. UGA Extension has great publication titled Basic Principals of Pruning Woody Plants, https://secure.caes.uga.edu/extension/publications/files/pdf/B%20949_4.PDF. What I love about this one versus some of the others, is that not only does it explain the different cuts, but also the reactions to those cuts. It also has some wonderful diagrams to go along with the explanations. When we understand how to properly make the different cuts to get the different reactions, we stand a better chance of getting the results we want. If at any point you have more questions about this or any other topic, please do not hesitate to call us at the Fayette County Extension Office at (859) 257-5582. Thanks!