Answer: Most hollies have a fairly regular symmetrical outline naturally and so do not need much, if any, routine trimming. If however you plan on shearing it into a hedge or a formal type shape, you can do that. This will limit or prevent berries from forming because of the way they are produced. (The berries ripen late in the season, they form where flowers grow, the flower buds grow on old wood from the year before.) If you want to trim yours, do so in late winter and early summer.
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