Q.Boxwood shubs
I have boxwood shrubs that suffer decliners due to winter cold or wind. What is a good fertilizer to feed them and when should I feed them? I live along the coast of North Carolina.
There is no regular fertilizer guideline for Boxwood.
The most reliable guide is a soil test to determine if there is a Nitrogen deficiency.
The first signs of a deficiency is yellowing leaves, generally will start on the bottom branches and work it's way up.
If you determine that your plants need a fertilizer, use a granular urea 10-6-4 or something similar.
Scatter around the drip line as this is where the most active roots are.
Do not over fertilize, as this can lead to root burn.
Here are some links to help you.
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-winter-protection.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/boxwood-care.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm