It's always important to let us know where you are located so that cultural questions can be answered more helpfully.

If you are wanting to shear your holly, I would not do that at this time of year. The outer foliage is providing protection. If you simply want to take a little nip here and there, no problem.

Probably, the worst time of year would be in the late summer/early fall when pruning could trigger a growth response in the shrubs....the last thing you want to happen at that time of year. If you are in NJ, I'd probably wait until late winter/early spring.

What are you planning on doing to your holly?

NJ, zone 7. Thanks, I will wait until the spring then.

The only problem I see with pruning or shearing them now is that they won't start growing until late Spring and will appear cut back for a long period of time. Normally they are pruned just before, or when, growing to minimize the time they look fresh cut.
I have never seen any winter damage to them when pruned in the winter, but I live in Zone 8 and the lowest temps so far have only been down to 4 degrees F.
Mike

Here's some in my garden a little over 8 ft. tall, almost 9 meters. They have not been pruned or sheared. I will cut back on the lawn to give them more room instead.
Mike

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