What's bugging you? August 24, 2016
By Jim Leser
Published Thursday, August 25, 2016 8:10 am
Having spent much of my early childhood growing up in the northeast, I have a keen appreciation of the fall glory of maple trees, especially sugar maples. We even had a term for trips where we enjoyed fall color while driving down country roads. This term was leaf peeping.
So you can understand that I long for the fall colors of my youth. And I am not alone. Many easterners and midwesterners who moved out west also miss these beautiful trees. Oh, the yellows and sometimes reds of our aspen trees are in fact spectacular but nothing compares to the reds and oranges of maples.
Now this is where it gets tricky. You can't plant just any old maple tree in our area of alkaline, high pH, salty soils. That is unless you want a tree with yellow and sometimes burnt leaves all season long. You see, many of the best maple tree cultivars grow in loamy, neutral to acid pH soils.
So let's look at the various kinds of maple trees and see if any fit our area's soil conditions. The Norway Maple, Acer plananoides, will grow okay in our soils as long as it is not planted in a hot site and the soil around its roots is not allowed to dry out. Otherwise you can expect leaf scorch in the summer. Two worthwhile cultivar examples are "Deborah" and "Emerald Queen." The petioles of the Norway Maple leaves will ooze a milky sap when pulled off the branch.
The Red Maple, Acer rubrum, is a species found in the eastern half of the U.S. and is not suited to our area. It is subject to iron chlorosis, or yellow leaves. The Silver Maple, Acer saccharinum, is extremely sensitive to our alkaline, high pH soils. Not only will their leaves turn yellow but often will dry up and be shed in mid-summer. Both the red and silver maple species are not recommended in our area. The Sugar Maple, Acer saccharum, is another eastern maple not recommended for our area because of problems with iron chlorosis.
The Bigtooth Maple, Acer grandidentatum, is sometimes found at nurseries and can do well in our area. It is a native in some of our western canyons. There are several other U.S. native and foreign maple tree species but they relatively are minor participants in the nursery trade. A foreign species of maples used in a cross I particularly like is the Shantung Maple, Acer truncatum. Two named hybrid cultivars of a cross between the Shantung Maple and the Norway Maple are the "Pacific Sunset" Maple and the "Norwegian Sunset" Maple. Most people can't tell these two apart but their fall leaf color transitions from orange to various shades of red. I planted one in my yard and it is awesome!
Another maple cultivar common in our western nurseries is the "Autumn Blaze" Maple. It is a cross between the Red Maple and Silver Maple. It generally does not do well here.
My overall maple tree recommendation for our area would be to avoid those that have Silver Maple in their pedigree. Otherwise you will be looking at an annual struggle trying to compensate for the inability of these kinds of maples to extract iron from our soils. This means applying as a soil or foliar application, a chelated iron product such as FerriPlus®. Good luck with that. Sometimes it works and sometimes it doesn't. Then what you are left with is watching your tree die a slow death rather than enjoying a beautiful, thriving shade tree with the bonus of spectacular fall color.
Jim Leser retired to Cedaredge in 2007 after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.