The question of whether the common Bradford Pear tree has thorns requires distinguishing between the nursery-sold cultivar and the tree in the landscape. The cultivar Pyrus calleryana ‘Bradford’ was specifically selected to be a thornless ornamental tree. This cultivated variety, popular in urban and suburban settings, does not typically produce sharp, woody spurs on its branches. However, its wild parentage and propagation process often result in thorny growth appearing on or near the tree.
The Cultivated Bradford Pear: Typically Thornless
The ‘Bradford’ pear cultivar was developed from the wild Callery Pear (Pyrus calleryana) and released in the 1960s as a desirable, low-maintenance urban tree. A key characteristic was its smooth, unarmed branches, a trait specifically bred to be absent from the wild species, which typically possesses sharp thorns. This thornless habit made the tree safer and more appealing for planting along sidewalks and in home gardens. The cultivated ‘Bradford’ pear is characterized by its dense, upright, and pyramidal growth when young, maturing into a broad oval shape. It is also popular for its glossy green foliage, showy white spring blossoms, and brilliant fall color, ranging from clear red to maroon.
The Source of Thorns: Reversion to the Wild Callery Pear
The confusion about the Bradford Pear’s thorns stems from its origin as a cultivar of the wild Callery Pear. This wild species, native to China and Taiwan, is naturally aggressive and heavily thorned. The wild type of Pyrus calleryana produces shoots with sharp thorns up to three inches long.
The cultivated ‘Bradford’ tree is typically created by grafting a thornless ‘Bradford’ cutting onto the rootstock of a wild Callery Pear seedling. This rootstock is genetically separate from the cultivated top portion and retains the wild species’ characteristics, including the potential for thorns.
When the cultivated portion is damaged (such as from pruning or storm breakage), the wild rootstock can send up new growth known as suckers or sprouts. These sprouts originate below the graft line and possess the full genetic traits of the wild Callery Pear, meaning they will be heavily thorned. This phenomenon, where a cultivated plant expresses the traits of its ancestral parent, is referred to as reversion.
Furthermore, the ‘Bradford’ cultivar, though initially thought to be sterile, can successfully cross-pollinate with other Pyrus calleryana cultivars, resulting in fertile seeds. Birds consume the small fruits and spread these seeds, which germinate into new, wild Callery Pear trees. These wild offspring are genetically unselected, invariably have sharp thorns, and are the primary source of the thorny pear thickets that have become an invasive problem in many regions.
Identifying and Safely Removing Thorned Growth
Thorny growth on a landscape ‘Bradford’ pear almost always indicates that the wild Callery Pear rootstock is actively growing. These thorny shoots are easy to identify because they emerge from the base of the trunk, from the root system below the soil line, or below the graft union. The thorns themselves are distinctive, appearing as long, needle-like spurs up to three inches in length. It is important to remove this thorny growth as soon as it is noticed to prevent the wild rootstock from overtaking the cultivated portion of the tree.
Homeowners should use heavy leather gloves and eye protection before attempting to prune or remove the sharp growth. These thorny suckers should be cut back cleanly to their point of origin on the trunk or root, being careful not to leave behind any stub that could simply sprout again. If the entire tree is being removed, cutting the trunk flush to the ground is only the first step, as the wild root system will vigorously attempt to resprout with multiple thorny shoots. To prevent this, the freshly cut stump must be immediately treated with a specialized herbicide containing active ingredients like glyphosate or triclopyr. This chemical travels down into the root system to kill the aggressive wild rootstock.