Answer: You have a asked a tough question! If you know which holly (variety name) you have, then you will be able to purchase a suitable "better half" by name. There are known fruiting pairs with, in most instances, a specific named male variety being used to pollinate a number of named females. The females will then produce berries. For example, within the Meserve group of hollies, 'Blue Stallion' is a pollinator for a number of females with Blue in their names.
There are many different hollies, however, and not all males are compatible pollinators for all females. You may be able to figure out what variety you have by comparing a branch tip with foliage (and possibly blooms in the spring), with hollies at the nursery. Nurseries usually stock both males and females and so should be able to help you locate the matching plant you need. You might also consider purchasing a fruiting pair of what seems to be a similar variety and see if your current plant begins to fruit. That way, you will have three shrubs, at least one of which should produce berries!
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