Whelp, it looks like this week I'm actually posting before the last possible minute. Wünderbar, da?
Winter draweth nigh, my friends; November is halfway over with, and we are only a month away from the Solstice, from the Midnight of the year. Most of the deciduous trees have lost their leaves, and are standing barren and bald for their many months' coma. But, even aside from the evergreen trees, the Pines and Firs and Hollies, there are a few species of trees that, though deciduous, stubbornly hang onto their dangling organs even to this late of a date. Now, O Gentle Readers, you have probably already deduced that this week's Tree, Pyrus calleryana, the Callery Pear, is just such a tree, or else I wouldn't have brought up the subject. And you are quite correct. Indeed, I chose it for this week because, not only has the Callery Pear not lost its leaves yet, but many of the individuals of the species that I have seen around the Chicago Area have not even had their leaves change colors yet.
Those leaves are oval-shaped and have a somewhat glossy tinge. They are some two or three inches in length and are darker in color above than they are below. Long into November do they persist on their branches, slowly changing from their chlorophyll-laden green to their native color, a fiery and flamboyant red, often streaked with gold. But so long do they take to change colors that, should the cold hand of Jack Frost come even a little early, the leaves will die from frostburn before they can all manage to change. This has not happened this year, though, and right now many of the Callery Pears near my apartment are half summer-green and half autumn-red, disrobing themselves slowly over these last weeks of fall.
Pyrus calleryana is by no means a large tree; at the very outside it can grow to sixty feet. Nor is it very long-lived. A Callery Pear should consider itself very lucky indeed if it sees its third decade. It is in some ways because of this smallness of stature and briefness of life that it has gained such favor as an urban tree. In new-built suburban shopping districts and subdivisions, outside of office buildings and industrial parks, along the medians of busy commercial streets: in all of these places does P. calleryana find that a home has been prepared for it by landscape architects and arborists. In these locales, its small size and neat, rounded, symmetrical crown have made it a favorite, for it neither takes up too much space nor does it disrupt the geometrical lines and curves of the modern architect's designs. Furtermore, its short life can be awfully convenient, for should the shopping mall or office complex need to be knocked down to pave the way for new developments, well, what of it? It's not like the little pear tree was going to live much longer anyway.
The tree also has the attraction, for Urban planners, of the magnificent semiannual shows it puts on. For not only does the species burst into the kinds of colors that make transcendentalist poets go into ecstasies every fall, but also in spring does it burst into flower in a most spectacular fashion. These white, five-petaled beauties appear before the leaves have fully unfolded from their buds, giving the tree, for a few short weeks, a charming and fantastic appearence. P. calleryana can also boast of having a reasonable tolerance for poor urban soils, able to withstand both highly compacted and highly loose dirt profiles, surviving acidic earths, and not minding exceedingly dry and exceedingly waterlogged dirts both.
But all of these advantages are not enough, in the eyes of many, to make up for the plant's equally numerous sins. The same symmetry and regularity of form that make it so attractive to some landscapers invite a dismissive scowl from others, and there are many who think it to be horribly over-planted. Furthermore, the tree pays for this geometrical order with a weak structure. The "crotch" angles (look, I'm not making this term up, folks, so don't blame me!) between the branches of many of the most widely planted varieties - including the 'Bradford' Callery Pear, millions of which have been planted across the United States - are extremely narrow, making them highly susceptible to breakage. Skillful pruning can somewhat alleviate the problem, but when a heavy enough thunderstorm or snowstorm comes through town, those branches will break. Other cultivars such as P. calleryana 'Aristocrat' - look at them flowers! - are stronger than the Bradfords, but they can still have problems.
The very popularity of the tree has also put it on the hit list of many environmental groups. Every fall, you see, starting in September and October, P. calleryana produces its pears. These aren't the large, curvy treats we are all familiar with - those come from the related species P. communis - but are rather small, hard balls a centimeter or so in diameter. These fruits are bitter and, to humans, mildly toxic, and are so hard as to be initially inedible to most everything. But they remain attached to the tree through the winter, and the regular frosts of that season will soften them up. After this suitable softening, they become eaten by birds of all sorts, who gobble them up and spread the seeds contained within the fruit through their foeces. P. calleryana is therefore spreading throughout the forests of the Eastern states, as the vast urban stands fruit each fall and have their seeds sown by the ever-helpful beaks of the birds.
This phenomenon has raised many environmentalists' hackles because P. calleryana is not in the least bit native to the U.S. No, the plant is, like so many famous ornamental trees, native to the Far East, to China, Korea, Japan, and northern Vietnam. And so this escape into America's wilderness makes it, in the watchful eyes of the ecologists, a villain of the first rank. In the Southeast, especially, in Maryland, Virginia, Delaware, and the Carolinas, the tree is becoming a real problem, and the National Arbor Day Foundation is no longer offering any variety of P. calleryana for sale. Personally, I am fond of this species. It is a handsome little fellow, and its wide range of colors help to brighten up Urban and Suburband areas. Up close, the well-proportioned leaves and its tangled, intertwining networks of branches give it a pleasing countenance. This being said, there's no way in hell that I'd ever be caught planting one of these in any garden I had control over, unless, of course, that garden were somewhere in the distant Orient.
Taxonomically, P. calleryana is, like all of its fellow pears, in the Rosaceae, the Rose family. The Rosaceae is both one of the largest - with some 3 or 4,000 species world wide - and one of the most taxonomically convuluted families of flowering plants. Traditionally, the family has been subdivided into several sub-families on the basis of fruit structure, but it is currently unsure whether or not these groups are true evolutionary units, and not just mix-ups of similarly seeming but not closely related species. Nevertheless, until more research is done (mm! research!), the genus Pyrus is placed in the sub-family Maloideae, along with the apples and hawthorns.
The Rosaceae as a whole is the family of not only the apples, hawthorns, and pears, but also of the blackberries, strawberries, raspberries, prunes, plums, peaches, almonds, cherries, apricots, and, of course, the Rose itself, most praised of flowers. It is a library of good things, and I have heard the rather charming claim made, by a professor at UIC at that, that while the Poaceae and Fabaceae (the grass and bean families, respectively) make human life possible, it is the Rosaceae that makes life worth living.
Making life worth living since 1986,
--mark
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