Blueberry bushes, part of the Vaccinium family, are just one type of berry-producing bush within that family. Close relatives include the loganberry, lingonberry, partridgeberry, whortleberry, and even the cranberry. Blueberry bushes are one of the few plants that is truly native to North America, though they can now be found elsewhere as well. They have several characteristics that set them apart from other bushes and berry-producing plants.
Observe the growth of the bush that you think may be a blueberry. There are a few types of blueberry bush. Those grown for commercial cultivation are usually Highbush varieties, which are exactly what they sound like. These bushes grow higher and produce berries that are easier to harvest, for that reason. Lowbush varieties are usually referred to as "wild blueberries." Some dwarf varieties exist as well. Not all blueberries are created equal, and these varieties will all taste slightly different from one another.
Observe the stems and branches of the bush. Blueberry bush branches are smooth and light brown in color. They may have some darker brown speckles, but the branches stand out in attractive contrast to the leaves, flowers and fruit. Blueberry bushes do not have thorns.
Observe the leaves of the bush. Leaves of a blueberry bush are dark green with yellow accents on the veins, and sometimes along the outside edges as well. They are smooth and do not have serrated edges. Leaf clusters are pinnate, and seem to grow in small groupings (6 or less). During fall weather, they turn many brilliant shades ranging from yellow through bright crimson, depending on the particular variety of blueberry bush. If the bush you are looking at is flowering, proceed to step 4. if the bush you are looking at has fruit, proceed to step 5.
Observe the flowers on the bush. Blueberry bush flowers are small, bell-shaped, and a pinkish-purplish-white in color. As birds pollinate them, they will give way to berries.
Observe the berries on the bush. Blueberries start out tiny and light lilac in color, and as they grow, become dark purplish blue. They have smooth skins, are round in shape, and are single berries. They do grow in clusters, like very small grapes, but that is where the similarity ends. You may sometimes see the shriveled remains of blueberry bush flowers clinging to the bottom ends of the berries, although these often fall off while the berries are growing. If the weather is dry, they will begin to crack and you will see dark purple juice ooze out.