Ash trees are often planted in the home landscape because they are in good supply in local nurseries and grow quickly compared with oaks. However, ash trees often are damaged by fall and spring snowstorms. Repeated storm damage often causes misshapen trees. Established ash trees should be pruned every three to four years to maintain good form and structure.
The varieties of ash available commercially are kinds of green or white ash. Green ash are more adaptable, cold tolerant and have golden fall color. There are three common varieties. Patmore has a pyramidal to oval shape and is seedless. Summit is more upright, but can produce some seeds. Marshall's Seedless has a rounded growth form, is seedless and less cold hardy than Patmore and Summit. White ash is known for purplish fall color. Autumn Purple has been selected for its intense red-purple fall color and is seedless.
Ash trees are home to many insects. The most common are ash sawfly, ash borer and oystershell scale. Ash borer is the most serious because it can kill the tree.
For more information, see the following Colorado State University Extension fact sheet(s).
- Cytospora Canker
- Aphids on Shade Trees and Ornamentals
- Oystershell Scale
- Shade Tree Borers
- Brownheaded Ash Sawfly
- Xeriscaping: Trees and Shrubs
- Trees and Shrubs for Mountain Areas
- The Science of Planting Trees
- Large Deciduous Trees
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Updated Monday, July 21, 2014