Feature Tree Archives - July 1999
Common Name: Hackberry
Scientific Name: Celcis occidentalis
This Tree in Colorado: Common hackberry is large shade tree commonly
planted in urban and community landscapes. It is popular because of its
vase-shaped crown structure when mature. The shape is very similar to American
elm but not as aesthetic. Because of its shape, it is recommended as a
replacement for the American elm. This tree is considered a Colorado native and
ranges in elevations from 4000 to 7200 feet, growing in wooded draws and
valleys. In developed areas, the seeds easily germinate often becoming a
nuisance in flower and shrub beds.
Growth Rate: Medium to fast growth rate. Can reach 30 feet
in 20 year period. Growth is not very uniform in early years. Branching habit
looks very scattered and in need of pruning during the first 10 years. It needs
pruning to make it look decent and to select a main trunk in these years. Soon
afterwards, it begins to develop the graceful arching structure which makes it
popular as a shade tree.
Landscape Use: Best suited for open areas and along streets. It
would fit well into the home landscape if there is a need for a large tree and
lots of shade. Planting close to the west side of the house (no closer than 12
feet) will provide comforting afternoon shade. The arching branches will shade
the walls and roof. Planted as street trees, hackberries provides an interesting
cathedral look similar to the popular American elm.
Best Advice: Grow in areas where the crown will have adequate space.
Mature crown diameter can reach 30-50 feet. Remember that it will look a bit
ugly in its early years and may need regular pruning to gain a strong main-stem
or leader.
Hardiness: USDA Zone 2-9. A very hardy plant for Colorado and it
is also tolerates draughty conditions and some shade.
Leaves: Leaves are alternate; simple; ovate to
oblong-ovate; 4" long and 2" wide with an acuminate apex; deciduous;
serrate margins; rough to touch; born on zig-zag brown twigs. Leaves nearly
always develop a small round gall on the underside.
Flowers: Not showy. The fruit is a small drupe about 1/4" in
diameter that ripens in September or October. Edible by birds.
Bark: Develops a characteristic warty look
when older; grey; smooth when young. Hackberry is easily identified by its bark
characteristic.
Insects and Disease: The most common appearance problem is the
hackberry nibble-gall which forms on the underside of the leaves. If severe, the
leaves do get disfigured. In most cases, no treatment is considered necessary.
Witches broom is also a problem in some areas. This characteristic is caused by
the abundance of twig and leaf growth in one area of the branch. It is often
caused by Eriophytes mite. From a distance, the trees look like they have
clusters of growth on the outer portions of the crowns.
Information Sources: Dirr, Michael Dr., "Manual of Woody Landscape Plants," 1990
Kuhns, Michael Dr., "A Guide to the Trees of Utah and the Intermountain
West,"1998