The ornamental pear, particularly Pyrus calleryana and its cultivars like ‘Bradford,’ is a familiar sight in urban and suburban landscapes. These trees are celebrated for their dense spring blooms and uniform shape, which led to their widespread popularity. Confusion arises because the name suggests a “pear tree” that appears to produce no edible fruit. This article explains the biology behind the tree’s reproductive cycle and the small, often unnoticed, fruits it produces.
Understanding the Fruit of Flowering Pears
Flowering pear trees do produce fruit, though they are not the large, sweet pears found in grocery stores. These small structures are technically pome fruits, the botanical name for the type of fruit produced by all members of the Pyrus genus. The fruits are generally round, resembling a miniature apple, and measure less than half an inch in diameter. They are hard and dense, appearing green or yellowish-brown, and are considered inedible for human consumption due to their astringent flavor.
The fruits remain attached to the branches throughout the fall and into the winter months. Their texture is often described as woody until they are subjected to a hard frost. This freezing and thawing process softens the fruit’s flesh. This makes the fruit palatable for wildlife consumption.
Ornamental Versus Edible Pear Varieties
The distinction between the flowering pear and its edible relatives lies in centuries of selective breeding. Ornamental varieties, derived from Pyrus calleryana, were chosen for traits like tolerance to urban conditions, attractive foliage, and profuse early spring blossoms. In contrast, commercial edible pears belong primarily to Pyrus communis, which was bred to maximize fruit size, sweetness, and desirable texture.
Individual ornamental cultivars, such as ‘Bradford,’ were originally thought to be self-incompatible, meaning a single tree could not pollinate itself. However, planting different Pyrus calleryana cultivars in close proximity defeated this intended sterility. When two genetically distinct cultivars cross-pollinate, they successfully produce viable seeds, often resulting in a heavy fruit set. Furthermore, many ornamental trees are grafted onto a seedling rootstock. If a shoot from this fertile rootstock flowers, it can cross-pollinate with the grafted portion, leading to fruit production.
Ecological Role of the Small Pears
The primary biological function of these small, hard fruits is to ensure the tree’s reproduction and seed dispersal. While unsuitable for human palates, the fruits provide an important food source for wildlife during the colder months. Birds, including starlings and songbirds, consume the fruits, especially after they soften following a frost.
Once consumed, the seeds pass through the bird’s digestive tract unharmed. This process removes the fruit pulp and disperses the seeds a significant distance from the parent tree via droppings. This dispersal mechanism is why the flowering pear has become an invasive concern in many regions. Its early leaf-out and late color retention allow it to out-compete native species.
Managing Seed Spread and Fruit Cleanup
The fruit production of the flowering pear creates two problems for homeowners: cleanup and invasive spread. The small fruits eventually drop to the ground, creating a messy layer that can rot on sidewalks and lawns, requiring regular raking. More concerning is the ecological impact, as the viable seeds germinate easily and revert to the wild Pyrus calleryana type.
Controlling Seedlings and Fruit
Escaped seedlings quickly form dense, thorny thickets that crowd out native vegetation, leading to the species being banned in some states. For existing trees, controlling seed spread is essential, accomplished by raking and removing fallen fruits before they germinate. For small, newly established seedlings, hand-pulling is effective, but care must be taken to remove all root fragments to prevent resprouting.
Tree Removal
For larger, established trees, complete removal is the most recommended solution for managing invasive spread. If the tree is cut down, the remaining stump must be immediately treated with a systemic herbicide, such as glyphosate or triclopyr, applied directly to the cambium layer. This cut-stump treatment is necessary because the tree will send up multiple shoots from the remaining root system if not chemically treated.