A picture tells a thousand words. If you trim a juniper bush too deeply, you get brown spots and typically it doesn’t come back.
“This juniper shrub is 5 feet high by 8 feet long. The brown spot on the lower right is where it was trimmed too deeply. That part will almost never come back,” David Merriman, Douglas county arborist said
“This is a good example because the top is untouched and doing fine. It just needed proper shaping. The overall bush will survive but it will always be prone to browning in that area.”