Blue Ash

Blue Ash

Family: Oleaceae
Latin Name: Fraxinus quadrangulata
Common Name(s): Blue Ash

Deciduous or Evergreen: Deciduous
Native Range: Central United States
USDA Hardiness Zone: 4-7
Mature Height: 50-75’
Mature Spread: 35-60’
Bloom Time: April-May
Native to Minnesota: No
Shade Tolerant: No

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Description:

Blue ash is a relatively uncommon species of ash in Minnesota that has become even more uncommon due to the Emerald Ash Borer. Leaves are opposite and compound, with 5-9 short-stalked, ovate leaflets. Twigs are corky and distinctly four-sided, hence the specific epithet. Flowers are bisexual, small, and numerous, emerging as purplish-green. The flowers develop into numerous samaras, which hang in clusters and disperse in the wind. The bark is grayish on mature trees, and separates into irregular plates. 

 

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Blue ash inner bark can be used for blue dye, hence the common name. Ash wood is hard, durable, and flexible and as such has many uses. It is perhaps most famously used for baseball bats, but also for furniture, boats, snowshoes, and numerous other implements.

The range for Blue Ash is much smaller than White Ash (F. americana) or Green Ash (F. pennsylvanicum), including small portions of Ohio, Indiana, Illinois, and Missouri, Kentucky and Tennessee. The town of Blue Ash, OH is named for the numerous ash trees in the area.

Blue ash is becoming less and less common in Minnesota due the presence of the Emerald Ash Borer (Agrilus planipennis), an invasive Asian pest. It was first found in Minnesota in 2009, and since has killed millions of trees. Minnesota has historically had a large concentration of ash trees, with over a billion trees, but the presence of EAB has been a disaster for the native population. EAB bores into the ash tree and eventually girdles and kills it. Many ash trees on the University of Minnesota campus, as well as in the Twin Cities, have been removed due to EAB damage.

To help combat the spread of EAB, do not transport firewood over long distances, and learn to identify EAB. See below for more information.

Issues:

Blue ash is susceptible, though seemingly less so than other ashes, to Emerald Ash Borer.

Other Resources:

Missouri Botanical Garden

UMN Extension - EAB

 

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