Answer: Evergreen hollies such as these are best pruned in the winter or early spring when they are dormant but temperatures are above about 40 degrees so the wood is not frozen when you cut it. Additional tidying can be done as needed during the growing season but it is best not to trim in late summer or fall. The reason for this is that trimming stimulates new growth and the resulting new growth might not have time to harden off sufficiently before the cold weather comes. This could cause extra winter damage to the foliage.
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