Instructions by Reid Smeda, MU Extension, for the Missouri Invasive Plant Council
Escaped Pyrus calleryanna (Callery pear) can grow densely along roadsides, unmowed fields/meadows, open woods, or any other open areas. Emerging seedlings will require up to 3 years to be noticeable from a distance, and up to 5 years before trees begin to flower.
Control of trees is easier when they are small.
Do not mow seedlings or small trees, as single stem trees will re-emerge as multiple stem trees.
To control trees from seedlings to about 6 feet tall, leaves can be treated with some formulation of glyphosate. An effective rate is 2-4 quarts per acre of a concentrated form (not the Ready-To-Use formulation) of glyphosate. If you want to mix only one total gallon of spray solution, add 4-8 ounces of concentrated glyphosate to 1 gallon of water. Mix the herbicide in water and add a small amount of surfactant (0.5% of final volume). Spray the solution on pear leaves and be sure to cover the entire tree. Be careful to avoid spraying adjacent desirable vegetation, because glyphosate can damage that also. Trees can be treated once leaves come out in the spring until leaves turn color in the fall. Damage symptoms are slow to develop (30 days) and complete control of treated plants can take up to 7 months.
An alternative to treating Callery pear leaves is to treat the base of the tree. Optimum timing for this technique is fall through early winter. Pour a small amount of a concentrated form of glyphosate into a small open-mouth jar. Identify a small, 1 inch diameter, disposable paint brush. Add a small amount of food coloring to the jar and stir to dissolve the food coloring (I like red or blue). No surfactant is needed. Using a chain saw or other saw, cut the Callery pear tree down and make the final cut across the base of the trunk until only a short (about 1 inch) stump is visible. Within 20 minutes of the final cut, paint the top of the stump with a thick coating of the red-colored glyphosate. If control is effective, you will not see any shoots come from the base of the stump.
Be sure to wear gloves and all proper protective equipment as described on the glyphosate label.
Let’s help our native trees and get rid of Callery pear!