Almost as desirable as Nellie Stevens, and better suited to Zone 5, is the American Holly, Ilex Opaca. Both it and the Nellie Stevens have special winter requirements, even in Zone 6 and definitely in Zone 5

Winter is the biggest fear with these hollies, so don't plant them fully exposed to Winter's coldest northwest winds. Cold dry windy air can kill the leaves, especially right after a few January days of 60-degree weather that cause the holly to send water back up.
Use anti-dessicant like Wilt-Pruf to get the holly ready for and through the winter. And make sure the plant is watered through the fall so its roots freeze in a wet state, so there will be water available should it turn warm.
Let me know how it turns out.

Well, I really don't know about zone 5 for hollies, but I will comment on Ilex opaca. For my tastes this holly is much, much more beautiful than Nellie Stevens or any other holly I know. Ilex opaca has a large number of cultivars. I don't know that many of them, but of those I have here my favorite so far is Satyr Hill. But these are hard to find at any local nursery.

--Spruce