Hello Mid-Ohio Valley farmers and gardeners! Everyone is enjoying the beauty of spring flowering trees and shrubs around the Mid-Ohio Valley. This spring you will notice hundreds of white blooming trees along the highway, interstate and even in rural areas.

Many of these white blooms belong to an invasive species, the Callery pear (Pyrus calleryana). If you have planted a “Bradford,” “Cleveland Select,” “Aristocrat” or “Chanticleer,” you have planted a variety of the Callery pear. It has become one of the most popular ornamental trees in North America due to its showy white flowers in early spring and beautiful fall foliage.

However, behind these beautiful white blooms lies a more menacing story. The Callery pear has become an extremely aggressive, non-native species with a tendency to spread along roadways and into natural areas through reseeding.

The ability to cross-pollinate allows these trees to reproduce via seed. Birds are attracted to the fruit and transport the seeds to natural areas where these trees can outcompete native vegetation.

How did all these Callery pears spread?

Here is where the quote “Life finds a way” from “Jurassic Park” is true. When first introduced, Bradford pear trees were supposed to be sterile. Since they were all genetically identical, Bradford was not able to cross-pollinate so fruits (and seeds) were never produced. New cultivars were introduced and were often commercially marketed as “self-sterile” or even “seedless.” This is true as long as each variety is grown in isolation.

For example, if there are dozens of Bradford pear trees planted in a neighborhood, they do not produce fruit. However, if someone plants another cultivar, such as Cleveland Select or Aristocrat in their yard, the new tree has the potential to cross-pollinate all the Bradford trees within a mile-wide range. This could result in a massive amount of fruit produced in a single year.

The seeds of this Callery pear cross-pollination are easily dispersed by birds. The trees are fast growers, quickly filling in open spaces and converting them to woodlands. Its ability to form dense thickets results in the shading out of native species, causing a rapid change in plant and wildlife diversity.

How do we control the spread of Callery pear?

On a national level, the cultivars of Callery pear are being phased out of the nursery industry. Many states are making it illegal to sell any of these trees and destroying inventory. However, the damage is done as thousands of these hybridized Callery pear trees are growing across the country.

What makes the situation worse are these wild pears are more hardy and vigorous trees than their parents. Amazingly, wild Callery pears have been observed growing as far north as Madison, Wisconsin, an area in which scientists never thought they could survive.

On a local level, please do not plant a Bradford, Cleveland Select, Aristocrat or other Callery pear. Due to their potential to cause cross-pollination and further spread of this invasive species, I would recommend you cut down any of these ornamental pears and replace them with a different species.

Callery pear is very persistent and will likely reinvade areas where it has been removed as long as a seed source remains nearby. If you cut a large tree, you need to treat the stump with a herbicide or it will resprout. Small seedlings which are hand pulled or mowed will resprout as well, so glyphosate or another herbicide may be needed for control.

Basal bark treatments are effective against Callery pear and can be applied throughout the year, except when snow or water prevent spraying to the ground line, to stems under 6 inches in basal diameter. Basal bark treatments use a concentrated solution (1:4 mixture) of the herbicide triclopyrester in basal oil applied to the entire circumference of the lower 12 to 18 inches of the intact stem.

What can I plant to replace an ornamental pear?

Serviceberry can be a good choice to replace Callery pear. It is a West Virginia native shrub with many aspects of landscape interest. It is available as a large, multi-stemmed shrub or can be trained to a small tree around 15-25 feet tall. It has a gorgeous white flower in early spring.

In addition, it has great fall leaf color, as the blue-green foliage of summer gives way to shades of gold to reddish-orange in autumn. Many cultivars have been selected for their fall color, including Autumn Blaze, Autumn Sunset and Autumn Brilliance.

The native flowering dogwood (Cornus florida) can also replace the Callery pear. It reaches 15-20 feet in size with a rounded form and white spring blooms. The showy white “flower petals”

are actually bracts that ring the smaller yellow-green true flowers at the center, which produce beautiful raspberry-like reddish fruit that last into autumn and attract wildlife.

The non-native Kousa dogwood (C. kousa) has a longer and later bloom season than the native flowering dogwood plus different growth characteristics and a greater tolerance for dry conditions.

Another choice is the American plum, an ornamental with large flowers and relatively big fruit. It is a small tree (max 35 feet) with a short trunk, many spreading branches and a broad crown.

In spring, it displays fragrant, white flowers in showy, flat-topped clusters. The fruit ripens to a shiny, bright red in August or September. In fall, the foliage ranges from red to pale yellow.

Plums can be eaten fresh and used in jellies and preserves and are also consumed by many kinds of birds. Numerous cultivated varieties with improved fruit have been developed.

Another popular alternative is the flowering crabapple (Malus spp.), a small to medium-sized ornamental tree suitable for urban environments. They have colorful spring flowers, (sometimes blooming up to four weeks) ranging from white/pink to red and reddish-purple.

There are more than 650 different cultivars of crabapples with a variety of leaf, flower and fruit colors, fruit sizes and growth forms.

Crabapples are tolerant to a wide range of soil conditions, as long as they are well drained. It is important when selecting crabapples to not only select for ornamental value, but also disease resistance. In addition, it is best to select a crabapple with small-sized fruit that persists throughout the winter.

The American Fringetree (Chionanthus virginicus) can also be a replacement. It is a medium-sized deciduous tree that blooms in late spring. It is known for fragrant flower clusters with white fringe-like petals.

Other features are the smooth, silver-gray bark and attractive fall foliage. Fringetree is a host plant for several insect species, and the fruit is a food source for many birds, including cardinals and blue jays.

Carolina Silverbell (Halesia carolina) is a small to medium-size tree with beautiful, showy bell-shaped flowers. This native tree has no serious pest issues unlike some members of the rosaceae family. It attracts hummingbirds and can host several species of moth and butterfly caterpillars.

It will bloom after only a few years and has a long life expectancy. However, it can be susceptible to chlorosis issues in higher pH soil and does not do well in drought conditions.

Finally, a native tree choice could be the Eastern Redbud (Cercis Canadensis L.). It has a showy spring display of pink flowers, borne in tight clusters along the stems and branches. It will grow to a 15-30-foot tree with a short trunk and a rounded crown of spreading branches.

There are many options for homeowners and cities to replace varieties of Callery pear.Check out these options at your local nursery. Native species are always a great alternative.

It will most likely take decades to control this invasive tree, but you can do your part by removing it from your landscape and replacing it with a smarter choice for the environment.

Contact me at the Wood County WVU Extension Office 304-424-1960 or email me at jj.barrett@mail.wvu.edu with questions. Until next time, Good Luck and Happy Gardening!