Answer: According to your zip code, you are gardening in zone 5. This is the coldest area these plants can be considered winter hardy. As a result, they need protection from winter wind and you must take care that their soil does not dry out any time it is not frozen. They should also be mulched in late fall to cover their root area (do not allow it touch the stem/bark.) Maintain a mulch layer about three inches thick year round.
Since they are evergreen, they lose moisture through their leaves during the winter. Winter damage can occur due to sun exposure, wind or dry soil or a combination of these, and newer plants are more susceptible to this because they do not yet have established root systems. Based on your description it sounds as though they suffered some winter dieback.
You will need to trim off any truly dead wood. This will be off color dull brown or gray, dry and brittle, and it will snap off in your hand. Live wood will have green inside the bark. Begin at the tips and work your way down until you reach live wood. If necessary, trim a little more to restore a somewhat symmetrical look.
Hollies do best in a soil that is evenly moist yet well drained. Over or underwatering or poorly drained soil can cause yellowing or browning leaves. Keep the soil evenly moist like a wrung out sponge, not sopping wet and never dry. To know if you need to water, dig down with your finger. If the soil is still damp, do not water yet. When you do water, water thoroughly and slowly so it soaks down deep. After watering wait a few hours and then dig down to see how far it went; it can be surprising.
Hollies require an acid soil, so fertilize with a slow release fertilizer for acid loving plants such as Hollytone per the label directions. (If you have already fertilized this spring, do not fertilize again, wait until next spring.) This may help somewhat with the yellowing as hollies will yellow in soil that is not acidic enough.
I would suggest you run some basic soil tests and consult with your local county extension to make sure that the pH is suitable for hollies. If not, they will be able to tell you what to use (and how much at a time) to acidify the soil until it reaches an acceptable range.
Finally, if your shrubs are in a windy location, you might consider moving them to a more protected site with morning-only sun. This would be more favorable for them.
Your county extension should also be able to help you troubleshoot the problem(s) with your plants. Although I have mentioned some common problems, there are also some disease problems that could cause discoloration. If it is something that would require a chemical control, they would have the most up to date recommendations on what to use and how/when is best to use it.
Good luck with your hollies.
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