Question
Why are one of my holly bushes leaves turning up and curling up also. They are still all a nice green. Also, it does not seem to be as full as the other bushes near-by. Will this problem spread to my other bushes? Thank you in advance. Carol of Millville, N.J. The Holly City!

Answer
Hi Carol,

Since only one bush is affected, the problem you describe sounds a bit like chemical injury.  Curling and distortion of leaves is a very common symptom.  I would review the use of chemicals in the area to see if you can associate any chemicals with the injury.  Chemicals can drift on wind currents for relatively long distances (up to a mile or more) and they can often volatilize several days after application.  I would check out this angle and see if you can associate anything.  If it is chemical injury, depending on the amount of chemical, the bush may be able to recover.  

Another possibility I want you to check out is insect injury.  Sometimes insects can cause this type of curling.  If you have a hand lens or magnifying glass, it may be helpful.  Look at some of the affected leaves closely, especially the undersides.  You may see the critters themselves or evidence of insect activity.  I don't think insect injury is as likely because I would expect to find the insects on all of your holly bushes and not just one.  

Lastly, there may be a problem going on underground.  Sometimes holly plants will show leaf curl if they are suffering from soil-borne problems.  If you have ruled out the first two possibilities I mentioned, you may need to check this.  Using a shovel, remove some of the soil under the bush so that you can examine the roots.  Healthy roots should be light colored and abundant.  Roots that are unhealthy are sparse and they are often darkly colored.  If you should observe brown or black roots, this suggests a root rot problem.  Unfortunately there is no cure.  Sometimes, redirecting drainage so that the plants don't sit in standing water is helpful.  I have seen people dig a small trench so that water drains away from the plant rather than pooling under it.  When plants sit in very wet soils, it often makes root rot problems worse.

These are some of the best possibilities to determine the cause of your problem.  Hopefully, you can get to the bottom of this.  I would suggest that you continue to care for and water the plant as normal.  The best time to fertilize shrubs/trees is in late winter or early spring.  I would suggest that you do this next season.  If you do find insects, please write a description of what you are seeing so that I can suggest appropriate treatments.

Good luck,
Jen