Blackberries are produced on perennial shrubs known as brambles or caneberries, not trees. Confusion often arises because some tree-borne fruits, such as mulberries, bear a striking visual resemblance to blackberries. Blackberries belong to the diverse Rubus genus, which also includes raspberries and dewberries. Understanding the structure and life cycle of the blackberry plant, which features long, semi-woody stems called canes, clarifies why they are classified distinctly from true tree fruits.
The Definitive Answer: Blackberries are Brambles
The blackberry plant is botanically classified as a shrub, specifically a type of cane fruit or bramble. These plants are characterized by long, arching, or trailing stems called canes, which emerge from a perennial root system called the crown. The canes are semi-woody and generally covered in sharp prickles, though many modern cultivated varieties are now thornless.
A true tree possesses a single, large, permanent trunk that persists for many years. The blackberry cane structure is fundamentally different because it is transient, lacking the permanent, thickening trunk found on a tree. While the roots and crown are perennial, the individual above-ground canes are not permanent growth. The term “bramble” refers to the plant’s dense, thicket-forming habit, where new shoots continuously replace older ones.
Understanding the Blackberry Life Cycle
The roots and crown of the blackberry plant remain alive year after year, but the individual canes operate on a two-year, or biennial, cycle. This two-stage process sets the plant apart from permanent woody structures like tree branches. The first-year canes are called primocanes, which emerge from the crown and focus solely on vegetative growth, developing height and leaves.
Primocanes are typically green and flexible, growing throughout the first season without producing any fruit. After surviving the winter, these same canes enter their second year, at which point they are known as floricanes. The floricanes develop small lateral branches, flower, and subsequently bear the fruit. Once the floricane has produced its crop, its life cycle is complete, and the cane dies back to the ground.
Key Differences from Tree Fruits
The primary distinction between blackberries and true tree fruits, like apples or cherries, lies in the permanence of their fruiting structure. Tree fruits are borne on permanent, woody branches that persist and produce fruit for many consecutive years. These branches thicken and strengthen over time, forming the long-lived canopy of the tree.
Blackberries, in contrast, produce their fruit on floricanes that are only two years old and must be pruned away after their single fruiting season. The fruit of a tree develops on the same branch year after year, while blackberry fruit develops on wood that is scheduled to die back within months of harvest.
The misconception that blackberries grow on trees likely stems from the similar appearance of the fruit to those of the mulberry tree, which produces dark, aggregate fruits on permanent woody limbs. The ephemeral nature of the blackberry’s floricane makes it structurally impossible for the plant to ever develop a permanent, tree-like form.