The blackberry (Rubus allegheniensis) is a plant known for its delicious fruit this time of year and nasty thorns any time of year that make walking through a colony of them difficult and painful. It is normally found on disturbed areas such as timber harvests and neglected farmland.
The canes grow up to 8 feet tall, are green to red in color depending on age, and have leaves that form in clusters of 3 to 5. The flowers are white with five petals, and bloom late spring, identifying one of the many cold snaps (blackberry winter) common during that time of year.
The fruit exhibits a characteristic called pre-ripening flagging, meaning that the fruit undergoes a series of color changes as it matures. A typical berry begins an inconspicuous green color, gradually turning a bright red, and finally turning a deep black when ripe. This pattern is typical of several mid-summer fruiting species, including mulberry, raspberry, cherry, and blueberry. The color phases may serve to signal potential seed-dispersing animals that fruit is about to ripen, ensuring they remain in the area and feed on the ripened fruit. Doing so maximizes the probability of successful seed dispersal.
The sweet taste of blackberries is primarily to attract mammals, as birds generally have a poor sense of taste. Mammals that feed on the berries (besides humans) include the fox, raccoon, bear, fox squirrel, and mice. The many seeds of the fruit pass easily through the gut of animals, thus dispersing the seed with a little fertilizer to boot.
Not to leave out birds, blackberry fruit production is timed to occur after the huge flush of insect hatches that occurs from spring to early summer. Birds are very attracted to the fruit when insect protein is scarcer.
Besides using them to make a killer cobbler and jelly, mountain folk have used blackberries for medicinal purposes. Juice from the fruit is purported to ease an upset stomach, and my mom would can them for that reason. The leaves and root bark act as an astringent and were used to treat diarrhea, dysentery, and hemorrhoids.