Answer: Nellie R. Stevens often fruits well enough without a male holly nearby, but fruiting can be enhanced if there is one. You can use a male Ilex cornuta for this purpose, and if there are some in your neighbor's yard, for example, that may be sufficient without planting one in your own yard.
If you want to plant one, you would need to check with your local retailers directly and see what they might have in stock on hand. Monrovia plants are carried by independent stores nation wide and each store carries its own selection of plants. Unfortunately, I have no way to check what a specific store might have in stock on hand or be able to obtain for you. There is a zip code based dealer locator at the web site to help you with contact information for stores in your area.
Enjoy your hollies!
Q&A Library Searching Tips