Crabapple trees are a very popular choice for suburban lawns in Naperville and throughout the Midwest. The Morton Arboretum says, “Their spring blooming is so prolific and showy one can’t help but love these trees. They are exciting throughout the year, with craggy branches and persistent fruits in winter.” These gems will bring years of enjoyment to our outdoor living spaces, but are susceptible to annual fungi that we need to treat. This spring and summer, with long stretches of cool, wet weather, has left our crabapples more prone toward the apple scab fungus than usual.
If you’ve noticed spots on the leaves of your crabapple trees or on the fruit, they may have apple scab. The spots may be ¼ inch in diameter, and look velvety and dark in color. Leaves will probably turn yellow and drop. The fruit will look deformed. These signs of apple scab are common, and even more so in a wet year.
Caused by the Venturia inaequalis fungus, it spreads after a spring rain when spores are airborne, and begins to affects this year’s leaves and fruit. It should be treated when you first see signs, and can be controlled by applying protective sprays in early spring. Badly affected limbs can be pruned, and fallen leaves should be raked and removed. It’s important to remove diseased areas because the fungus can re-infect the tree throughout the summer, survive over the winter, and cause more damage the following spring.
Further preventive measures include keeping the trees pruned, avoiding overcrowding of limbs, cleaning under the trees, and spacing multiple trees to allow for adequate airflow.
If you’re thinking about adding a crabapple tree to your lawn, you will want to choose a variety that is resistant to apple scab. Information about different crabapple varieties can be obtained by visiting the Morton Arboretum website. If you want to keep your existing beautiful crabapple, you can manage and prevent the disease by using readily-available disease control products. Be assured that it is treatable, and with ongoing maintenance, your trees will continue to look beautiful year-round.
O’Donovan Landscaping has over 45 years of experience in the Naperville area, designing and installing beautiful landscapes and hardscapes for residential and commercial customers. We want you to enjoy your trees and shrubs for years. Our designers can help you select the best tree or shrub for your outdoor living space. Call us at 630-355-3370 and set up an appointment.