January 21, 2016 – Kenosha News
Emerald ash borer has and will kill thousands of ash trees in Kenosha. Trees increase property value, provide energy savings, improve human wellbeing, encourage tourism and decrease crime rate. For these reasons and more it is crucial to replant. Over the next few weeks we will look at large sized (over 30 feet) trees.
First, a few general thoughts on tree selection. A diversity of tree species in a neighborhood or community lessens the impact of insect or disease outbreaks (e.g, Dutch elm disease, emerald ash borer). In other words, don’t plant the same tree as your neighbors. Characteristics to keep in mind when choosing trees are cold hardiness, soil conditions, growth rate, mature size, ornamental characteristics, resistance to insect or disease problems, required maintenance, and invasiveness potential. No tree is perfect, so prioritize what qualities are important to you.
Maples come in a wide range of sizes and shapes. Most maples exhibit good to excellent fall color. They have shallow fibrous root systems that often compete with grass and other plants for water and nutrients, but make maples easy to transplant.
Sugar maples are native in Wisconsin. Their brilliant red, orange, and yellow fall coloration is the foundation of nature’s autumn display. Sugar maples are slow growing with dense oval crowns. Mature height in the landscape is 60 to 70 feet. These trees grow well in well drained, moist, fertile soil. In urban areas sugar maples should be planted in large yards or parks. They do not perform well as street trees.
Red maple has green leaves in summer, red fall color, and light gray bark. In the East it is a common street tree, but in the higher pH urban soils of the Midwest red maples may have problems with nutrient deficiency chlorosis. For locations with soil pH below 6.7, this is an outstanding tree.
The native silver or soft maple is sold as a fast growing, readily adaptable tree. However, they are not recommended for urban landscapes. They have brittle branches, poor branching structure, and a shallow root system that lifts sidewalks and gets into water lines.
A naturally occurring hybrid of red maple and silver maple, sometimes called freeman maple, is a good urban tree. These hybrids have the beauty of red maple and the fast growth of silver maple, without the problems of the parents. The freeman cultivar ‘Autumn Blaze’ is overused and should be avoided.
Norway maples, which were previously planted extensively as street and landscape trees, may become invasive in natural areas so should no longer be planted.
Barb Larson is horticulture educator for the Kenosha County University of Wisconsin Extension. She holds a master’s of science in horticulture from the University of Wisconsin-Madison. If you have a plant or gardening question, email her at firstname.lastname@example.org or call 262-857-1942.