Longtime residents of College Park will remember streets lined with blooming Bradford pear (Pyrus calleryana) trees, the one-time official tree of Prince Georges County. Currently, there are far fewer Bradford pear street trees in College Park and the official tree of Prince Georges County has changed to the native willow oak. Which brings us to the questions, why are Bradford pears no longer a preferred street tree and why was there a change in designation of the official County tree?
A bit of background first. Fruiting pear trees were introduced to North America by the early European colonists in the 1600’s. During the 1950’s, fire blight, a bacterial disease, began impacting fruiting pear trees on the West Coast of the United States. Scientists at the US Department of Agriculture in Oregon and at Glenn Dale, Maryland worked to develop a fire blight resistant fruiting pear tree by grafting Asian varieties of pear tree root stock onto fruiting varieties.
Researchers in Glenn Dale observed the durability of the Bradford pear and thought it would make a suitable street tree. They tested the tree along the bare streets of University Park, Maryland. The tree performed well and the push was on to introduce the Bradford pear to the nursery trade in the 1960’s. This tree species was also popular because it started blooming with an abundance of white flowers towards the end of March, which signaled that spring had arrived in Maryland. The shiny dark green leaves were attractive during the summer and changed to a pleasing burgundy fall color late in the season. These were some of the reasons why Prince Georges County adopted the Bradford pear as its official tree.
The original Bradford pear trees were self-sterile (unable to receive pollen from the same cultivar), but the new cultivar trees were able to send out root shoots whose flowers were cross pollinated by other varieties of pear trees, producing viable seeds. The fruit from these Bradford pears was then eaten by birds, and the seeds were dispersed by the birds resulting in Bradford pear trees growing along roadsides, in hedgerows, in woodlands and in fields throughout the United States. The Bradford pear is now considered an invasive species by the United States Department of Agriculture and the State of Maryland. The states of Pennsylvania, Ohio, and South Carolina have passed laws banning the sales of this tree species.
The Bradford pear has become an unpopular tree to plant due to several other reasons. The flowers, though beautiful, have an unpleasant odor. Bradford trees grow quickly and have a large crown with poor branch attachment. The roots of the Bradford pear are shallow making the tree susceptible to failure during high winds. The structural deficiencies of the tree species become apparent after about twenty years of age when the trees begin losing branches and self-destructing during storms due to their tight branching habit. These undesirable attributes have contributed to the recommended and systematical removal of Bradford pear trees from roadsides and city parks in many jurisdictions throughout the Eastern United States. Homeowners should consider replacing Bradford pear trees on their property before they reach an age when they begin to deteriorate.
Introduced Bradford pear trees can be replaced with tree species native to College Park that perform well as urban street trees. These native trees will help support pollinator species of birds, insects and mammals that are native to Maryland. Some of these trees are Sweetbay Magnolia (Magnolia virginiana), Fringe tree (Chionanthus virginicus), Eastern redbud (Cercis canadensis), Flowering dogwood (Cornus florida) and Serviceberry (Amelanchier canadensis). These are all flowering trees that bloom in the spring, however some flower earlier than others. A couple of larger trees that can be planted as replacement trees include the Tuliptree (Liriodendron tulipifera) and Southern Magnolia (Magnolia grandiflora). The Tuliptree is frequently visited by hummingbirds when its yellow flowers are in bloom.
Have questions about which Bradford pear trees in the City of College Park will be removed in the future and what replacement trees will be planted? Email the City Horticulturist at horticulturist@collegeparkmd.gov. Before planting any tree, please contact Miss Utility at 811 or via https://www.missutility.net/homeowner to request the underground utilities be marked to avoid future conflicts.