Sunday, July 29, 2007

Japanese Pagoda Tree

Dr. David Hosack is best known to history for the death of a famous patient. He ministered to Alexander Hamilton after Hamilton's duel with Aaron Burr. But Hosack had more success as high-profile botanist than high-profile physician. This Columbia College professor established the country's first botanical garden in 1801. His garden, now the site of Rockefeller Center, contained the first Japanese pagoda tree recorded in the U.S.(1) The original tree no longer exists, but Japanese pagoda trees have had a successful career in this country as shade trees.

Plainfield has small numbers of pagoda trees scattered around town as street trees, and they are in bloom now. The largest example I know is on Central Avenue between Second and Front Streets against Cooper's Office Furniture store. This nicely shaped tree has a trunk diameter of more than two feet.

Another handsome example is in the curbside strip at 1325 Evergreen Avenue, just to the right of the front walk as you face the house.

In the 1100 block of Park Avenue, opposite 1106, is another attractive pagoda tree, photographed in bloom on July 25.

Pagoda trees have been cultivated in the Orient for thousands of years. They were often planted near Buddhist temples. A gracefully shaped tree with delicate, feathery foliage, the pagoda tree is largely pest-free and is tolerant of dry soil and pollution --- very well suited to be a street tree. It offers the great advantage of flowering in midsummer, when few other trees are in bloom. Its fruit also is ornamental, resembling a bright green string of shrink-wrapped peas.

The tree grows quite large. Martha's Vineyard claims to have the oldest and largest example in North America. The island's giant pagoda tree was transported from the Orient in a flower pot in 1837 by a sea captain. He planted it in front of his new house in the center of Edgartown, where it still stands. The tree now has a diameter of about 7 feet at breast height. The telephone pole in the photograph passing between two of the tree's limbs provides a sense of scale.

The Japanese pagoda tree has a confusing overabundance of names. The tree originates from China, not Japan, and is also known as Chinese scholar tree. To add to the confusion, the botanical name was changed several years ago from Sophora japonica to Styphnolobium japonicum.

More on Bradford pears:

John Louise, chief of the Plainfield Shade Tree Bureau, tells me that his men don't call Bradford pears by their name. They call them "overtime trees". Another one of them split recently in front of 1433 Evergreen Avenue, losing a large limb. The wound, depicted below, shows bark trapped in what was the tight angle between limb and trunk. That trapped bark prevented the wood of those two parts from knitting together to make a solidly constructed tree, leading to the splitting so typical of Bradford pears.


The New York Times recently ran a front-page article on the existential threat to the baseball bat tree posed by an insect pest, emerald ash borer. I plan a posting on Plainfield's ashes and would appreciate hearing about noteworthy specimens.

(1) Leslie Turek "Plants in Historic Landscapes", Radcliffe Seminars, 1995 (

Copyright Gregory Palermo

Sunday, July 15, 2007

Bradford pear, beautiful but breakable

How do we love thee? Let me count the ways. For thy beautiful (if malodorous) white flowers in April! For thy symmetry, thy cone-shaped crown! For thy rapid growth!

Bradford pear (Pyrus calleryana 'Bradford') is surely one of the most popular trees for planting in the eastern United States. But our collective passion for this tree leads to broken hearts, not lasting relationships. Bradford pear is genetically programmed for a short life that often ends catastrophically.

The tree splits apart in storms because of the way it is constructed. The limbs extend out from the trunk at very narrow angles. This tight-angled branching pattern traps bark between trunk and limb. Instead of knitting together as they grow, the trunk and limb are separated by bark, with no bond holding them together. If they don't split, Bradford pears can be expected to live for about 30 years.(1) Many disappear because of splitting long before reaching that age.

The Bradford pear at 937 Hillside Avenue was planted 10-12 years ago. The photograph above shows its condition after loss of one of its three major limbs in the fall of 2006. Notice that the other two limbs have begun to split apart. The photograph below shows the tree from the other side. The crack follows the line of trapped bark.

Below: the same tree on June 7, 2007.

Below: The same tree three weeks later.

Its neighbor at 930 Hillside, planted at the same time and pictured below, has been reinforced by steel bolts to help to hold it together. It illustrates the good looks that make Bradford pears so popular. Notice the narrow-angle branching.

The tree at the top of the page, on West Fourth Street just west of Plainfield Avenue, is rather a long-term survivor. It was planted in about 1990 by a civic group in front of what was then the Plainfield Health Center building as part of a beautification project. City Councilman Elliott Simmons was one of the planners and planters of that project (but the blame for the choice of Bradford pear falls on me, not on Councilman Simmons).
Also still attractive is a row of Bradford pears on Leland Avenue at Cook School.

The Bradford pears on the Randolph Road side of Muhlenberg Hospital have not done quite as well. They look like a row of amputees. In fairness, it appears that not all of the amputations were spontaneous. I would guess that someone has pruned some of them to try to prevent splitting. That sort of pruning is not at all easy to do in an effective and attractive way because all of the major limbs typically spring from the trunk at roughly the same height above ground. Worse, as the tree gets larger, those closely spaced branch points intersect each other. The corrective pruning, to the extent that it can be done, tends to eliminate the symmetry of the crown that is one of the tree's attractions.

The name "Bradford pear" looks as American as apple pie, but this Bradford shares no bloodlines with the governor of the colony at Plymouth. The tree is a Chinese import. Although Bradford pear is sterile, attempts to breed less split-prone varieties of Pyrus calleryana have yielded trees that are capable of reproduction. They interbreed with Bradford pear and their brood has become an invasive pest.(2)

Lou Dobbs hasn't tuned into this Chinese threat yet, but the USDA Forest Service hasn't missed it, recently honoring the trees as "Weed of the Week".(3), a joint program of the University of Georgia and the USDA, offers this(4): "Do not plant Bradford pear. Seedlings and shallow-rooted plants can be pulled when soil is moist. Small trees need to be dug up or pulled out...ensuring removal of the root system. Large trees should be cut down and stumps treated with an appropriate systemic herbicide...or ground up to prevent resprouting. If cutting is not possible, trees can be cutting through the bark all around the trunk, about 6" above the ground." How do we kill thee? Let me count the ways.

Copyright Gregory Palermo