The question of whether a blueberry plant has thorns is common, often arising from confusion with other berry-producing shrubs. True blueberry plants, which belong to the genus Vaccinium, are entirely smooth and do not possess any sharp defensive structures on their stems or leaves. This absence of thorns is a defining characteristic, distinguishing it from many other wild and cultivated berries. The misconception likely stems from the close proximity of thorny plants that produce dark, rounded fruit.
Examining the Blueberry Plant Structure
Blueberry plants, including the common Highbush (Vaccinium corymbosum) and Lowbush (Vaccinium angustifolium) types, have a smooth, woody structure that lacks any sharp appendages. Botanically, a thorn is a modified stem, and a prickle is an outgrowth of the plant’s epidermis. Blueberries produce neither of these features, making the plant safe to handle and harvest.
The stems of blueberry plants are typically covered in smooth bark, sometimes dotted with lenticels used for gas exchange. Highbush varieties grow as tall, deciduous shrubs, often reaching heights between six and twelve feet, with smooth canes growing upright from the crown. Lowbush blueberries, sometimes called wild blueberries, are much shorter, generally growing as a sprawling groundcover between six and twenty-four inches tall.
These plants are woody perennials that develop multiple shoots, or canes, from the base, known as the crown. While the older wood can become stiff and brittle, the smooth surface remains consistent. This structure allows for easy harvesting, which is a significant factor in the commercial cultivation of the fruit.
Mistaken Identity: Thorny Look-Alikes
The belief that blueberry plants have thorns is usually due to confusion with other plants that bear similar-looking dark fruit. The most frequent source of this error is the Rubus genus, which includes Blackberries and Raspberries. These plants, often referred to as brambles, have stems covered in numerous small, sharp prickles.
Blackberry fruit is an aggregate of small drupelets, creating a bumpy surface, which contrasts with the smooth, true berry of a blueberry. Another plant often confused with blueberries is the Gooseberry (Ribes genus). Gooseberry shrubs are armed with sharp spines along their woody stems, and some varieties produce dark, purple-black fruit that can resemble a large blueberry.
Distinguishing these plants lies in the stem and fruit formation. Blueberries have smooth stems and the fruit grows in clusters, while thorny look-alikes have sharp stems and the fruit often forms differently. For example, wild plants like Greenbriar (Smilax species) or certain Buckthorn shrubs produce blue or black berries on thorny vines or branches, contributing to misidentification.