Good Intentions - Bad Tree

Although they have never been on my A-list of trees, I must admit that the local display from the ornamental pear trees (Pyrus calleryana) has been remarkable this year. The flowers have been blooming now for close to three weeks and have managed to escape the blossom browning freezes that mar them in some years. They have also not been subjected to sustained spells of early heat that can cause the flowers to fall too early and the leaves to appear too soon. They are so stunning this year that you can't help but notice the sheer number of them that have been planted. From corporate office parks, to school yards, to street side plantings, to subsidised housing projects; ornamental pears trees are everywhere. With the exception of crape myrtle (Lagerstroemia), a local favorite - P. calleryana would be the most widely planted ornamental tree. Another thing made obvious by this year's display of blooms - just how many pears seem to have escaped the bounds of cultivation. There are more than a few places here where Pyrus is becoming the dominant tree species. While these wild stands are very pretty right now, the showy blossoms hide an ugly truth. When native ecosystems are altered by invasive species, plants and the animals that evolved with them are pushed out. The story of how this species has gotten to the point of invasiveness reminds me of Dr. Seuss's The Cat in the Hat Comes Back, where each effort to solve the problem of the pink cake stain only creates another pink problem.
Pyrus calleryana is native to China, Japan and Korea, and was brought to this country in the second decade of the 1900's. Researchers were hoping that its resistance to fire blight could benefit the edible European pear (Pyrus communis), which at the time was being decimated by the bacteria. Later in the 1950's it was noticed that this species could make a contribution to the horticultural as well as the agricultural world, and one particularly cultivar stood out - 'Bradford'. Like most P. calleryana, 'Bradford' exhibited disease and insect resistance, it flowered profusely starting at a young age, had a rapid growth rate, clean dark green foliage and had amazing late fall color. The overall shape of the tree was very tight and symmetrical and individual specimens showed a great degree of similarity with each other. It was also tolerant of pollution, heat, drought and the occasional flood. Hardy from zones 5 to 8, it was the perfect street, parking lot and residential tree for a good part of the nation. A landscape architect's dream come true, and if it never existed it would have to have been invented. They were planted everywhere by the tens of thousands.
There was one not so little problem with the perfect tree. As it aged those tight dense branches that grow at a very narrow angle were weak. Entire sections of the tree would collapse to the ground in wind and ice, ruining the shape which no pruning could ever restore. As this problem became apparent, fewer 'Bradford' were planted, but more of the varieties with a stronger branching structure were. 'Aristocrat' and 'Chanticleer' (aka 'Cleveland Select') became the pears of choice. When the streets were full of 'Bradford' pears there was little problem with them being invasive because they are self infertile. Now that these new varieties are being planted, often near older stands of 'Bradford' all of the cultivars are mingling with each other producing fertile fruit. These are being eaten and disseminated by birds, and now pears are coming up everywhere. These new pears seem particularly prone to growing in disturbed soil where most other vegetation has been removed. The same qualities that make the pear such a widely durable street tree, also make it uniquely suited to adapting to life outside of cultivation. As if all of this was not disturbing enough, now thorns are appearing on the trees after not being seen on the cultivated varieties. Perhaps this will provide more secure shelter for their friends the birds and possibly keep the deer and the groundskeepers away.
Should anything be done with species, like the ornamental pear or the Canada goose whose DNA makes it possible for them to thrive in the ecological opportunities humans (perhaps nature's most adaptable species) have inadvertently created for them?

For more detailed, scholarly information about Pyrus calleryana and its invasiveness you can read:
The Beginning of a New Invasive Plant
by Theresa M. Culley and Nicole A. Hardiman
or
On the Spread and Current Distribution of Pyrus calleryana in the United States
by Michael A. Vincent

For different perspectives on different trees you can visit:
Festival of the Trees - a monthly blog carnival for all things arboreal, which will be hosted next month at The Marvelous in Nature.

Killing Time

I start working a 6 day schedule next week, so nagging little mundane tasks that I have been putting off must be attended to. One of which was to get the slow leak fixed in one of my tires. The unusually pleasant people at Firestone said it would take about an hour. So to kill time and to get some exercise I took a power walk downtown. Heading down Granby I stopped at the Federal Building. They had these concrete planters out front that went up within a year of the Oklahoma bombing to prevent a repeat performance in Norfolk. You would never know they were there for security, you would think they were just planters. Each was planted with several Magnolias whose cultivar I did not immediately recognize underplanted with Vinca minor. I would have liked to have spent more time here but there was a very loud man trying to get me to heed his warning of the impending Apocalypse about to befall all of us.

Today the Federal Building is a sedate off-white and blue green, but when I first came to Norfolk the building was red-orange brick with lots of bright orange glossy trim. It really stuck out from the surrounding buildings, and I kind of liked it, but I think I was in the minority. I remember that there was once a plaque that said it was the Jimmy Carter Federal Building, (not the James Earl, but Jimmy). In the 90's the bold red brick starting peeling off of the face and the entire exterior had to be rebuilt, even thought it was less than 20 years old. When it was rebuilt the look was completely changed.

This afternoon on the back side of the building were three brave souls protesting the detainment of prisoners at Guantanamo. When I was making my return trip they were replaced by a man wearing a sandwich board advertising the final close out sale for a nearby jewelery store. I thought that this was such a timely transition from mucking up overseas to economic meltdown.

The farthest point of my walk found me in the churchyard at St. Paul's. Built in 1739, this church is the oldest building in Norfolk, and today is a green oasis in the middle of the city. It was the only building to survive the bombardment and torching of Norfolk during the Revolutionary War. There is a cannonball fired by Lord Dunmore in 1776 embedded in the brickwork. This is considered precious metal around here. The entrance also happened to be marked by the same Magnolias.

Here is a postcard photo showing what St. Paul's looked like at the turn of the last century.

This leather postcard was sent by great grandfather in 1907 when he was courting my great grandmother. He was one of the only relatives I had who was not from the Eastern Shore and I have about 4 more of these postcards showing the beach and harbor. Apparently his efforts worked.

Next on the mundane task list, laundry and get the Liriope cut back. I'll spare you the photos.