As bud break is currently occurring on early species in southern and central Indiana, remember to be on the lookout for callery pear (Pyrus calleryana) on properties that you manage for removal. Callery pear (multiple cultivars in the landscape from this species) has become a major invasive species of concern in wild and disturbed areas in the Midwest after escaping from managed landscapes.
-
- Figure 1. Callery pear close to bud break in West Lafayette, IN.
The first cultivar introduced as an ornamental tree was Bradford. This was the lone cultivar available in the landscape for many years. With callery pear being self-infertile, there were not any fruit found on callery pear in the landscape when Bradford was the only cultivar. When other cultivars were introduced into the landscape, fruit production started to proliferate. As escaped plants began to grow in wild areas (aka more diverse genetics), fruit production increased.
-
- Figure 2. Callery pear flower.
-
- Figure 3. Callery pear in flower in a landscape.
Nurseries in the state have greatly reduced, or eliminated, growing callery pear, but they are still readily available in some box stores. It is important to discuss with the property owners that you work with about replacing callery pears on the property, and new planting installations, with species that are not invasive.
-
- Figure 4. Invasive calllery pear flowering in wild area.
-
- Figure 5. Fruit set on callery pear. Photo: Rosie Lerner, Purdue Extension.
Identifying callery pear is most practical in early spring, when they are the only trees that have prolific white flowers before bud break on most plants, or in late fall, when they hold onto dark purple/maroon leaves longer than most other species. By flagging trees in flower for removal, you can get back to them when the season slows a bit in summer or fall. Control measures are much easier and more effective when the plants are small, so scouting for newly germinated or young seedlings is an important part of your integrated pest management program.
Related information:
Now is the time to Identify Callery Pear https://purduelandscapereport.org//article/now-is-the-time-to-identify-callery-pear/
Ornamental Pear Fallout https://purduelandscapereport.org//article/ornamental-pear-fallout/
Invasive Plant Species: Callery Pear https://www.youtube.com/watch?v=yvnd13TJUJc
Alternative Options for Invasive Landscape Plants https://www.extension.purdue.edu/extmedia/ID/ID-464-W.pdf
The Beginning of a New Invasive Plant: A history of the ornamental callery pear in the United States https://academic.oup.com/bioscience/article/57/11/956/234351
