These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Using Birches in the Landscape
April 6, 2000
Spring is a popular time to think about adding shade trees to the home landscape. Among the popular choices are birches, which may or may not be a good fit for northern Illinois landscapes. Proper selection, location, and care are needed to assure a healthy birch.
Paper birches, Betula papyrifera, are popular due to their ornamental white bark and overall growth habits of the tree. Unfortunately, white birches are very susceptible to a destructive insect called the bronze birch borer that kills many birches every year. Thinning of foliage and dieback of branches, starting at the top of the tree, is characteristic of bronze birch borer damage.
The most borer resistant white birch is Betula platyphylla, sometimes called the Japanese white birch. In particular, the cultivar 'Whitespire' has been promoted as borer resistant. Keep in mind that borer resistant does not mean it is immune to borers, as some 'Whitespire' trees have been attacked by borers when under extreme stress, especially older trees.
An alternative to white birch to consider is the River birch, or Betula nigra. This species does not have white bark, although the cultivar 'Heritage' has very light colored bark. River birch is an excellent tree that can tolerate both wet and dry soils, and is not considered susceptible to bronze birch borer. On alkaline soils, however, chlorosis (yellowing of foliage) may be a problem.
Paper birches are often under extreme stress when growing in northern Illinois landscapes, making them prone to borer attack. In fact, drought in the late 1980's has lead to extensive borer damage even in northern Wisconsin, where the paper birch is native.
To help assure a healthy white birches, avoiding planting them in high stress areas, such as near pavement and on higher spots in the landscape. Mulch under the tree, instead of having grass, may help reduce some stress on birches. In addition, be sure to water during dry weather and extreme heat of summer.
Contact your local Extension office for current pesticide recommendations.
Certainly no tree is immune to problems. However, the paper birch is very prone to serious borer problems when grown in northern Illinois. Proper selection and care will help assure healthy birches.