So what to plant as a replacement for your sick ash? First of all, you will need to determine how much sun or shade gets to the site where you want your new tree to grow. How big will it get? What shape it is full grown? And most of all, what type of soil do you have in that area.
One tree that can be pruned to the vase shape of the ash is a tough native, the hackberry. It gets 40 to 80 feet tall at maturity and has only cosmetic problems, leaf galls and witches brooms, that can be pruned out. And best of all, its zone 3 hardy.
If you’d like a tree that makes a statement, look for a Kentucky coffee tree. Forget the name; it is a native with good adaptability. The leaves have a fine texture, but it’s the bold branching habit and textured bark that make it a stand out in the winter. The female has large chunky pods that are a real hazard to the lawn mower so get a boy tree instead. Listed as a zone 4 but does well here. That is unless you plant him on the top of a hill where the northwest winds hit him all winter. He gets 40 to 60 feet tall. Also zone 3.
If you want fall color, look to the Freeman maple. It’s a natural hybrid of red and silver maples. A zone 3, again, 40 to 60 feet tall. Cultivars are Sienna Glen or Firefall. Autumn Blaze is also a cultivar but has proven to be less hardy here.
If you have the room for the extensive root system to spread and want a large tree, 50 to 80 feet tall, look to cultivars of sugar maple. Fall Fiesta, Bonfire, Crescendo and Green Mountain are available. This is a beautiful large zone 3 tree.
If you don’t mind acorns and the squirrels that closely follow them, look to the pin oak and the red oak. These two are fastest growing of the oaks. Oaks will grow as fast as any other tree if planted in good soil, watered and fed well. Both of these oaks have beautiful red fall color and a handsome shape. To diminish the threat of oak wilt (not here at the present) plant them well apart so there is no chance of the roots touching. And never prune any oak from April to October. These trees will grow 50 to 80 feet tall and again are zone 3 hardy.
The height of any tree depends on growing conditions. Poor soil, drought, poor site, will result in a shorter less healthy tree. Not many trees do well in sandy soil, on top of a windy ridge, or if they must deal with dry conditions year after year. You need to love your trees. Give them water, good soil, proper pruning and they will air condition your yard in the summer, slow down wind in the winter and add thousands of dollars of value to your property. What more could anyone ask.