By Bev Johnson

Master Gardener

Everybody loves sugar maples – the beautiful fall color, the light dappled shade, and their spreading shape. Unfortunately, they do best in the cool shaded edge of the woods, not in the middle of the yard, in the full sun where they are usually planted.  Our hotter and often drier summers may well be their death knell as it also may be for the birches, pines, and spruces. Experts suggest that hardy maples and red oak will replace them. Of course, there are other factors that can kill a tree besides warmth; soil compaction, strong hot winds, disease, and the frequency and intensity of fall rain can all kill trees. We can expect more tree-killing insects like the ash borer to live through the warmer winters now.

The University of Minnesota is working to develop a maple that will live and do well in these changing conditions. The Woody Landscape Plants Breeding Project has test sites at the Minnesota Arboretum, the Outreach centers in Grand Rapids and Morris and in the U-More Park in Rosemont. These test sites are working on trees that will survive in our freeze to boil weather conditions. One tree they are working on is the maple. For instance, they are crossing our native sugar maple with a Caddo Maple. The Caddo is native to the Caddo mountains of Oklahoma. They are more drought and heat tolerant than our native maples. They hope that the cross will have a better ability to cope with hot dry summers, and dry winters.

They are also working with some Asian maples that are very drought tolerant, crossing them with Norway maples. The Shantung maple is medium sized, domed-shaped, has purple leaves in the spring, and has good fall color. The University has introduced other Asian trees and shrubs like the amur maple that have proved to be very hardy, often crowding out our native trees.   

Woodrow Nelson, a spokesman for the for the national Arbor Day Foundation, thinks we may see sycamores, shingle oak, chinkapin oak, bald cypress and hickory trees beginning to move north as they are as close as Iowa. That doesn’t mean you should start ordering trees and plants from Nebraska. We still have pretty hairy winters that can kill a marginally hardy tree or perennial in a heartbeat.

Pagoda Dogwood is a small tree that should be planted more than she is. She has an architectural shape, wide at the top that is a perfect accent for a house with a low profile. She has been short lived because she is susceptible to a fungus (golden canker) that kills her. There are trials that are attempting to develop a resistant cultivar.

No tree or shrub will thrive if planted in the wrong place, wrong soil or badly planted. You can’t just dig a hole, drop a tree in it and forget it and expect it to do well. Start with the hole. Three times wider than the root ball and only several inches deeper than the top root. The trunk flare needs to be above the soil line. Your new baby will require supplemental watering for the next five years. Check the tag on your plant to determine if it wants shade, part shade or full sun. What kind of drainage? Some trees like damp feet, but that will kill others. No tree or shrub will do well in a wind tunnel, like one zipping around the side of a building. Give your new baby the proper TLC and you will have her for as long as you live,—-probably not if you are 90.