celtis / hackberry
The hackberry, while often forgotten by casual consumers, is commonly heralded by tree experts as “one tough tree.” Found on a wide range of soils east of the Rockies from southern Canada to Florida, these trees thrive in a broad span of temperatures and on sites that vary from 14 to 60" of annual rainfall. They can even stand up to strong winds and tolerate air pollution. All of this hardiness adds up to a good landscape choice, particularly if you’re looking for an energy-conserving shade tree that doesn’t require watering.
**The above text is borrowed from Arbor Day Foundation's website**
Celtis occidentalis / common hackberry
This moderate to rapid grower is very adaptable to the extremes of urban conditions, including drought and windy conditions. The bark is cork-like and rough in texture.
Height: 50 - 75 ft
Spread: 50 ft
Fall Color: Yellow
USDA Zone: 4 - 8
CARE: POSITIVES & DRAWBACKS
There are many desirable traits of the hackberry. It is a native tree in parts of North Dakota. A cousin to the popular Elm tree, this is a fairly fast growing tree. Small flowers produce tiny half-inch dark brown to black fruits that are food for birds and other wildlife.
While there are many pests that can choose this tree as a host there are few things that actually succeed in killing this tree. Powdery mildew is a problem in more humid climates. Aphids, particularly woolly aphids like this and Elm trees as a host. Aphids are treatable with available insecticides. One of the more common problems this tree exhibits in this region is that it is a host for a nipple gall. (A photo can be seen below)
nipple gall on common hackberry
This commonly seen infestation is practically harmless to this tree. It is a result of an adult insect laying eggs that hatch on the leaf. The larvae hatch and begin to feed on the leaf. When the chew they excrete a substance that causes abnormal cell growth. The plant (both as a means of control AND as a result of the excretions of the insect) grows over the insect and seals it in a "gall". This is called a nipple gall because of it's shape. Often this insect attempts to overwinter in the gall of the leaf. Raking and disposing of these leaves can lessen and sometimes eliminate this problem.
Pruning of this tree is best done in late summer as the leaves begin to turn and or when the tree is dormant in late winter and spring before the tree leafs out.
For more on identifying old wood and new wood see our page on care of woody plants.