Holly bushes were damaged during the winter
Holly bushes were damaged during the winter. Brown leaves. How far down can I trim them and can I do it now (April)? The brown leaves go far down to the main stem. The bushes are about 12 years old. I've trimmed them gently every year. They look bad.
Here is an article about holly pruning that you might find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/holly/trimming-holly-bushes-how-to-prune-holly-bushes.htm
You can prune back the branches to the live growth (green tissue), but you should wait until after the last frost date. Call your local Extension Service https://www.gardeningknowhow.com/extension-search/
for information on that date.