Organic Answers Column – April 6, 2022
My Love Affair with Trees – Especially the Right Kind of Ash Trees
My love affair with trees began years before I became a landscape architect, the Dirt Doctor, and an arborist. As a kid I loved to climb trees at home in Pittsburg, Texas, where my favorite two were mimosa and catalpa. It’s easy to know why I liked them best: the bark was smooth and easy on the skin. Later I went to school at a little college in Lubbock and it was during my trips back home that it hit me how cool big beautiful green trees are.
 Texas ash |
 Autumn color in Texas ash |
My first horticulture course was the start of my rebellion to go along with what I was told. My teacher, while explaining various trees, went on a rant one class about how terrible the catalpa tree was. Little did he know that I was a catalpa tree expert. My first smoking experience was a catalpa bean pod. It was also during these early years that I learned at school and from people in the industry how terrible ash trees are. Well, some are bad, and some aren’t. Let’s review.
Arizona ash is found naturally in canyon and riverbanks, but is a terrible tree choice for homeowners. They share a similar problem with cottonwoods in that they are appropriate to their native sites but no good in neighborhoods on property with homes. The reason? They don’t live long enough and have several built in problems. Some of my contemporaries agree with that assessment but make a serious mistake by saying that all ash trees are bad. The Arizona ash and bottomland ash are not good landscape trees, but there are some excellent ash trees that should be promoted and used more often.
 The wafer ash has interesting foliage and seed pods |
 The giant swallowtail butterfly’s favorite foliage is prickly ash |
The Texas ash (Fraxinus texensis) is on the top of the good ash list. It tolerates most soils, is relatively pest free and drought tolerant, has beautiful fall color that ranges from yellow to deep reds, and is a strikingly graceful and beautiful tree. It also lives a long time.
Three other good ash trees are wafer ash, prickly ash and fragrant ash. The wafer ash (Ptelea trifoliate), also called hoptree, is an excellent small tree for use in a broad range from Texas to Chicago. Prickly ash or toothache tree (Zanthoxylum clava-herculis) is another small deciduous tree normally found along hedgerows, in thickets and on edges of forests in the central and eastern portion of the country. This wonderful little tree has a special feature – it is host to the giant swallowtail butterfly. Third, the fragrant ash (Fraxinus cuspidata) is a true ash and a terrific tree that grows from Texas to Nevada. It has strongly fragrant white flowers that resemble those of the fringe tree (Chionanthus spp.). These are all worth trying and there’s more detailed information if you follow the links to dirtdoctor.com.
 Fragrant ash has beautiful sweet-smelling flowers |
 The Texas ash has a graceful profile in winter |
Yes, all the ash trees are possibly subject to attack by the imported emerald ash borer, but there are two good points there. The ash trees I like are not as susceptible as Green ash, Arizona ash and the like. Also, I have the solution to the infestation if it does occur. It’s called the Sick Tree Treatment.
