Raspberries belong to the plant genus Rubus and are cane fruits grown for their sweet, edible berries. Most wild and traditionally bred raspberry varieties possess sharp, stiff growths along their canes, leaves, and stems. While these structures are often called thorns, botanically, they are something quite different.
Prickles vs. Thorns: Clarifying the Terminology
The sharp points on a raspberry cane are technically classified as prickles, separating them from true thorns and spines. In botany, a true thorn is a modified stem or branch, and a spine is a modified leaf part; both contain vascular tissue. Raspberry prickles, however, are merely outgrowths of the plant’s epidermis, the outermost layer of cells. This structure means prickles lack the internal vascular tissue found in thorns and spines. Because of this superficial attachment, a prickle can often be snapped off cleanly from the cane without tearing the underlying wood.
The Evolutionary Purpose of Raspberry Prickles
These sharp epidermal outgrowths serve two primary functions. The most obvious role is mechanical defense against grazing animals, such as deer and rabbits. The dense covering of prickles deters large mammalian herbivores from browsing on the plant. Prickles also provide a defensive barrier against smaller threats, including various insect pests, by impeding the movement of invertebrates across the plant’s surface. Furthermore, the recurved nature of some prickles helps the long, arching canes anchor and support themselves by gripping surrounding vegetation, allowing the canes to gain better access to sunlight.
Practical Guide to Thornless Varieties and Handling
Thornless Varieties
Plant breeders have developed several smooth-caned raspberry cultivars for gardeners seeking to avoid prickles. Popular thornless varieties include ‘Joan J,’ a primocane-fruiting (fall-bearing) type known for its large berries and high yield. Other choices are ‘Canby,’ a floricane-fruiting (summer-bearing) variety that is nearly prickleless and winter-hardy, and ‘Caroline,’ a vigorous, upright cultivar. Although smooth canes are appealing, some gardeners find that prickled varieties offer superior flavor or greater hardiness in specific climates.
Handling and Maintenance
When dealing with standard prickly varieties, safe handling involves wearing thick, puncture-resistant gloves during pruning and harvesting. Raspberry canes are biennial, meaning they live for two years, and prickles are most prominent on the new first-year canes. Pruning out the old, fruited canes close to the ground immediately after harvest helps manage the density of the thicket. This regular maintenance improves air circulation and plant health.