Ash Trees in the Urban Landscape
Ash Trees in the Urban Landscape
Common Ash Tree
Why is it that Ash trees became so popular to plant anyway? Green, Black and White Ash are native over a large portion of the US and Canada. Many nurseries have some incredible selections from the native species that are seedless, have great fall color, and beautiful upright and rounded forms. Municipalities, homeowners, and Landscape Architects began noticing the beautiful seedless selections that were coming on the market. They began being used on most all the projects not only because of their varied forms and fall color, but because of their adaptability of different soil types, and hardiness. If you have ever seen an Autumn Purple Ash in fall color, you know just how unbelievably and intensely gorgeous they can be. Too much of a good thing maybe? You would think we would have learned from our past mistakes by lining so many streets and urban plantings of American Elm only to see the demise of such a stately tree from Dutch Elm Disease that has wiped out so many trees. Thus, plant hybridizers and nurseries have developed so many different new Elm selections that are Dutch Elm Disease resistant and we are now able to grow many different cultivars once again.
Damage Caused By Emerald Ash Borers
The same thing has happened with the way we were using (or I should say overusing) Ash trees in the landscape. Who would have guessed that we would import a bug that bores into the trunks of all the different kinds of Ash trees and eventually kills them all? What no one really expected is that borers typically only affect trees that are stressed or not healthy, but the difference with this bug is that it wildly attacked every single healthy Ash in its path. Movement was slow and eventually we figured out the movement of dead Ash firewood was being transported to many campgrounds and people moving infected wood to their cabins and summer homes in heavily wooded areas that contained many native Ash trees. Many years later, we have yet to introduce a resistant Ash tree to the market. The bug continues to spread slowly and in all directions taking out all Ash in its path. What is the answer? Diversity is the key when it comes to all urban landscapes. A healthy urban forest includes many different kinds (many different Genus) smartly planted without a monoculture of any one kind of tree. Planting many kinds of trees alternating with different Genus is the key. Should I treat the Ash I have in my yard? Treatment is available and if you have a very important specimen in your yard, you may want to consider having it treated. What many are finding out in areas that are infected, they are spending their money on replacing those Ash trees instead of treatment.
Look at how far the Emerald Ash Borer has moved across the US. Scary. So, what are some trees that are taking the place of Ash? What should I plant in my yard? There is not one single tree that is taking the place of Ash for the exact reason mentioned earlier; diversity within the landscape. Nature Hills sells trees across the entire U.S., so specific trees that do best in your area will automatically come up for your hardiness zone to best assist you with your selection. It is not a good idea to line your driveway or lot with all the same kind of tree. Strategically planted deciduous trees (trees that lose their leaves) on the southwest side of your home will produce shade from the hot afternoon sun. In the winter months, those trees lose their leaves and allow the sun to warm your home in the afternoon. Some trees that might be used to replace Ash in the landscape or street trees keeping in mind a tree similar in size include the following:
Maples (Norway types, Red maple types, Sugar Maple types, Silver Maples, and many hybrid types), Buckeye, River Birch, Catalpa, Hackberry, Yellowwood, Ginkgo, Honeylocust, Kentucky Coffeetree, Tulip tree, Ironwood, London Plane tree, Poplar, Oak varieties, Black Locust, Sassafras, Linden (especially American Sentry), and Elm (many Dutch Elm Disease resistant varieties available).
There might be some smaller trees that you should consider using in place of an Ash:
Lilacs (tree form), Mountainash (not an Ash, but does need a cool moist soil), Callery Pear, Flowering cherry, Flowering plum, Crabapples (many excellent and clean growers), Magnolia, Hawthorn, or Beech selections.
However you choose to handle your existing Ash trees in your yard (treat or remove) if your Ash trees do become infected, just be sure to select trees that are hardy for your area, will work in the soil type you are planting them into, and one that has some interest. Keep a mixed urban landscape by including plants that are not in your neighborhood or overplanted in your area. For specific help, please let us know if we can assist you with selection for your area.