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.
March 22, 2009
March 20, 2009
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.
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.
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.
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.
March 14, 2009
Bloom Day - The Cruelest Month
The Wasteland is perhaps T.S. Eliot's most famous poem and it begins with the line "April is the cruelest month,...". While it is probably a crime to even mention his masterwork with the dribble produced here, it is clear that Mr. Eliot lived in another climate and did not work at a garden center. For me, March is the cruelest month. Even though we are only two weeks into it, we have already had school closing snow, gale force winds, temperatures in the teens within days of temperatures above 70, sunny skies, thick overcast, sleet and now it has been raining since last Thursday and it is not forcasted to end until early this week. At work we must make sure we have enough plant material for the warm sunny days when customers come out of the woodwork, but we can't get too much in case the weather changes. We are constantly in an epic struggle to pull plants out of their protected winter homes into the warm sunshine, only to have to move them back in again or cover them with blankets when it all changes, not to mention what to do with the truckloads coming from California, Alabama or Texas. Whether we have good weather or bad, many sales or few, we still must pay for what we bring in.
At least at home, the garden seems to be on a more normal, if not slightly delayed schedule. The cooler temperatures that we have had this winter have kept blooms more in line with what is typical then what they have been in recently previous winters. Certainly the star of the early March garden are the Narcissus - please don't ask me which ones they are, the nurseryman does not keep track, but he loves them nonetheless.
Another signature plant of early March would have to be Forsythia. I do not know exactly which cultivar this is, but it has variegated gold and green foliage and blooms about a week after the others start.
At least at home, the garden seems to be on a more normal, if not slightly delayed schedule. The cooler temperatures that we have had this winter have kept blooms more in line with what is typical then what they have been in recently previous winters. Certainly the star of the early March garden are the Narcissus - please don't ask me which ones they are, the nurseryman does not keep track, but he loves them nonetheless.
Another signature plant of early March would have to be Forsythia. I do not know exactly which cultivar this is, but it has variegated gold and green foliage and blooms about a week after the others start.
Behind the Daphne in the picture above you can see another vigorous plant, Camellia japonica 'Crimson Candles'. This variety is more cold tolerant, blooms as prolifically C. sasanqua and the new foliage is red.
Camellia japonica 'Les Marbury'
Camellia japonica 'Les Marbury'
Camellia japonica 'Nuccio's Gem'
I like the blue green foliage and shrub-like form of this Corydalis more than I like the flowers. I do not know with certainty what the species is, but most likely it is C. lutea. Each plant seems to be an annual or maybe a biennial, but I think every single seed is fertile and it comes up everywhere, but is easy enough to pull out.
The last shot is Vinca minor that came with the house (I would not have planted it) next to my favorite groundcover Trachelospermum asiaticum 'Ang Yo'.
Please visit Carol at May Dreams Garden to see what other gardeners are posting for March's Garden Bloggers Bloom Day, and while you are there be sure to say thanks for her herculean effort.
Sandy's Plants
Yesterday I was able to attend an open house at Sandy's Plants in Mechanicsville, Va. which is northwest of here just outside of Richmond. While it was cold, rainy, overcast and downright miserable in Tidewater, it was all that plus snowing and sleeting there, not the best day for touring Sandy's. We get a portion of the perennials we sell at work from Sandy's, and though that is not my area of responsibility, I thought it would be fun to go anyway. Friday's are normally a day off for me, and it was probably as good a day to go as any, if the weather had been nice I would have wanted to stay home in the garden.
Sandy's Plants Inc. was founded by a former school teacher oddly enough named Sandy. She had a knack for growing and dividing Creeping Phlox and Candytuft and started selling them. Now they offer close to 2800 different plants which are found in garden centers all over the mid-Atlantic. Most of the plants are grown uncovered outside in the elements perhaps giving them a little extra sturdiness. When you visit they have golf carts available for you use as you search the fields and tour the display gardens, which are not just filled with plants, but with fun sculptures too.
For the open house we were shown a Power Point display of the new plants they are offering for 2009, quite a few of which did not make it into the catalog. We also got to see many of the plants they are growing as part of the Stepable program. These are plants that you can put between stepping stones or in other crevices that can take varying degrees of foot traffic. We have sold these types of plants longer than there has been any kind of special program, and I like our name for them better - Crack Plants, but I am sure with its drug connotations that name would not be as marketable. In addition to being fed well, we each got to take home a couple of plants gratis. I snagged a Rudbekia maximus and a Sedum 'White Diamonds'.
Behind the building where we met was a wooded display garden, and of course at this time of year Hellebores were well represented, but there were other things to enjoy as well.
Finally, some of the sculpture.