We still need to know where you are! Zone 6 is a large swath of the country - give us your state and nearest big city, so we know if you're in the mountains, by the ocean, in a marsh, in a desert....

I am in northern Maryland nearest big city is baltimore

Dwarf Burford holly or similar. Needs to be fertilized.

Yes, Dwarf Burford holly.

We have been here for a year and definitely haven't seen berries. After reading about them they should produce berries. Do they produce them right away or after a few years?

Dwarf Burfords try to bloom really early. Quite often their flowers (even foliage) are fried by late frosts. This happened to mine the last two years. I would say the further north you are in their range, the less chances you have of getting good berry set. If you can get Hydrangea macrophylla to bloom in your region, you should get Burfords to berry up those years. But it's all in the timing of the spring cold outbreaks.