Plant Profile: Fraxinus pennsylvanica

Fraxinus pennsylvanica, commonly referred to as Green Ash, is a deciduous tree that can reach heights of up to 65 feet, and in some cases, even 120 feet, with a trunk diameter ranging from 2 to 3.5 feet. Young specimens, characterized by their soft, silky hairs on twigs, leaf undersides, and petioles, are often called Red Ash. In contrast, mature trees display smooth leaves and branches, earning them the name Green Ash.

The leaves of this tree are arranged oppositely and are pinnately compound, typically consisting of 7 to 9 leaflets. The bark is a gray-brown hue, featuring shallow furrows and crisscrossing ridges that create an x-pattern. In early spring, small flowers, which are light green to purple and lack petals, bloom in loose panicles. The female trees produce a single-winged, dry, flattened samara with a slender seed cavity that ripens in the fall, often resulting in a significant litter when they drop. For landscaping purposes, male trees are generally favored since they do not bear fruit.

Green Ash is the most widely distributed species among ash trees, thriving in various environments and soil types. Its adaptability allows it to withstand drought, wind, moderate salinity, and alkaline conditions. This species is commonly found in low-lying areas and swamps, particularly along brown water rivers and the lower regions of the Piedmont and North Carolina mountains, though it is seldom seen in disturbed mesic upland sites.

In terms of pests and diseases, planting new Green Ash trees is no longer advisable due to their vulnerability to the emerald ash borer. This invasive pest can decimate an ash tree within 3 to 5 years of infestation, and once established, it is extremely challenging to eliminate, as it feeds beneath the bark and burrows into the wood. Native to Asia, the emerald ash borer was first identified in the United States in 2002 and has since spread to several states in the Northeast and Upper Midwest, posing a significant threat to all ash species in North America. Additionally, Green Ash trees are prone to various other insect issues, including the lilac borer, carpenter worm, oyster shell scale, leaf miners, fall webworms, ash sawflies, and ash leaf curl aphids. They may also face potential diseases such as fungal leaf spots, powdery mildew, rust, anthracnose, cankers, and ash yellows, with general ash decline being a notable concern. Furthermore, brittle branches are particularly vulnerable to damage from strong winds and ice or snow accumulation.