Most cultivars are largely self-incompatible so they require cross-pollination from another cultivar. It insures you'll have larger fruit and earlier fruit maturity. The more plants you have, the more fruit you get. Provided the birds don't get them 1st. I was in Home Depot in Frederick last week and they had 3 different types of blues. Lowe's only had blueberry roots sold in a small box. I passed on the boxed one and instead picked up 2 nice size plants from HD...bringing my total # of plants to 7 so far.

It's important to amend your soil BEFORE planting blues. Blueberry plants grow best in acid soils (pH 4.0 to 5.0) that are well-drained, loose, and high in organic matter. There are several ways to accomplish this. See the link.

BTW, my soil ph is slightly on the acid side and in spite of warnings to prepare the soil a year in advance, I didn't. I added soil acidifiers 2 wks prior to planting. My plants are fine but maybe I just got lucky.

Here is a link that might be useful: How to acidify the soil

To get blueberrries you need more than one plant since they can't self-pollinate like some other berry producing plants.

One possibity for your plant getting fruit that first year is that you dug it up from the woods after it flowered and therefor it was already pollinated by other wild blueberries.

Also make sure your blueberries get full sun for the most fruit. If they start getting shaded out by tree branches the fruit production will be reduced.