Blueberries are native to the United States. The berries were eaten by Native Americans and Pilgrims at the first Thanksgiving. Today there are over 450 species of blueberry bushes that grow around the world. These bushes require acidic soil, but may be grown in containers where acidic soil is not present. The foliage will change as the seasons pass and as the bush grows.
For centuries, Native Americans revered blueberries in folklore, and the growth of blueberries controlled their seasonal migrations. Natives even made teas from the leaves, and told stories about the foliage of the blueberry. In spring, before the berries grow, the plant produces a blossom (calyx) that forms in clusters on the end of its stems. The fruit grows from these star-shaped blossoms, which is why Native Americans called them 'star berries.'
When most people think of blueberries, they think of the Highbush blueberry, a cultivated strain of blueberry that was developed in the early 1900s. The Highbush blueberry differs from wild strains of blueberry in that the berries are larger, plumper and easier to pick than wild blueberry varieties. The North American Highbush accounts for 90 percent of the world's blueberry production. Highbush blueberries are distantly related to cranberries and azaleas. By contrast, Lowbush blueberries may be grown as groundcover, due to the fact that the bushes seem to hug the ground. These cold-hardy plants may grow as far north as the arctic circle, and are a favorite in New England, where they grow in boggy areas that berry farmers call "the Barrens." These low-growing bushes have smaller berries that some berry farmers consider to be superior in flavor to Highbush berries. Their leaves turn bright red from early fall until the first New England snows in October.
The North American Highbush Blueberry is a deciduous shrub, meaning that it produces leaves in spring, and sheds them in the fall. Other species of blueberry are evergreen, which means that they maintain leaves year 'round. Leaves among the various species of blueberry bush range in shape from egg-shaped to lance-shaped. The North American Highbush blueberry produces oval or egg-shaped leaves. The leaves are thick and waxy, with smooth edges. The leaf's structure and size are designed to minimize evaporation and conserve water.
In the spring, new buds begin to form on the canes of the blueberry shrub as the plant moves out of its dormancy cycle. The first leaves do not have the characteristic thick, waxy cuticles that mature leaves have. At the same time that the new leaf shoots form; flower buds also begin to grow at the end of the canes. The earliest flower buds of the season are larger, and will produce larger fruits than later buds.
As the plant moves into the drier summer months, the leaves mature and their cuticles thicken. The buds of the flowers mature into fruit, which ripens and turns from a green to a purple-pink and then to a deep blue-purple color. At this point, the leaves and shoots stop growing, and all the plant's energy goes into growing and maintaining the fruit. The peak month for fruit production is July. However, fruit will be produced throughout the rest of the summer. In the fall, the leaves of the blueberry bush will change color and begin to shed. Wild varieties of blueberry, including the American Lowbush, will turn a vibrant red color. During this time, flower buds also begin to form for next year's blueberry growth.
The terminal bud on the blueberry cane is the bud from which the fruit will grow. All other buds on a blueberry branch will produce leaves. However, if a terminal bud dies, then the next bud down the cane will become the new terminal bud and switch from producing leaves to producing flowers and fruit.