- Written by Kevin R. Lee Kevin R. Lee
- Published: 04 April 2018 04 April 2018
This post is about Fraxinus rather than Sorbus Trees. Ash are a important group of eastern forest hardwoods. One does very well here in Calgary. One may not sound great but out west we take what we can get. Slowly advancing westward after the last ice age, the green ash is native as far west as the beautiful rolling ranch country of southern Saskatchewan. The Tree is naturalized here, mainly the result of the annual prolific seed output from the female trees.
Ash are Dioecious plants, with male and female flowers on separate Trees. The single winged seeds have a excellent germination rate. You will often find Ash volunteers in hidden and neglected spots.
A stalwart westerner, the Ash has commonly been used as a shelter belt Tree on many prairie farmsteads. In the city it has been used as a street Tree from the beginning and the many giant (for here) Trees in the neighborhoods of Mount Royal and Elbow park are a pleasure to see. It is quite drought resistant with a deeper than average root system, which I learned the hard way by once digging one up. Like all Calgary's Trees it will thrive rather than survive if watered properly.
Not without a few problems, Ash are seriously tough Trees, a first string player. Western ash bark beetles can prey heavily; looking back to the early 90s we had a serious infestation in the city and many weak Trees were killed. The adult female beetle overwinters in the ground and in spring crawls up the Tree to lay her eggs in the upper branches. The Larvae need energy and they eat a series of galleries under the bark. Their feeding activity usually extends around the branch, girdling it. Once cut off from its water and nutrient source, the branch dies. You can easily spot larva feeding in their galleries by a sap stain, a dark stain on the bark. I have used this staining to easily identify which branches to prune out. If we do have another population spike, tangle foot is one way of helping catch the ladies as they ascend.
Ash Trees are to a much lesser degree affected by the Ash plant bug, a sap sucker of leaves. It will impart white spots to the leaves. Another uncommon affliction is the fungus called Ash yellows.
Plant the male seedless clone called Patmore, water and enjoy, for generations.