Plant Of The Month
Ostrya virginiana
OK, let me say right up front that my main reason for writing about this tree has less to do with its landscape value (which is considerable) than fond childhood memories. Although I have seen this species in various arboreta, I haven't really noticed it in the landscape. Please note that I didn't say I hadn't seen it but rather that I hadn't noticed it.
On casual observation at a distance Ostrya virginiana bears a fair resemblance to the non-columnar form of European Hornbeam (Carpinus betulus) which is in the same family. Its wood is quite strong, which accounts for one of the common names. In the yard of my boyhood home there was a specimen of this tree that was just perfect for climbing by a small boy. If it were not for that tree's strong wood I am certain that I would have done it in with my arboreal adventures.
The first and most obvious tipoff is the bark. The trunk of C. betulus is smooth and gray with a slight sinewy appearance similar to that of its cousin C. caroliniana. The bark of O. virginiana occurs in thin vertical, shreddy plates on young trees, a characteristic that moderates somewhat as the tree ages. There are some definite differences in the leaves as well. Those of O. virginiana are proportionally wider and the lateral veins often branch near the edges of the leaf while those of C. betulus do not.
Both O. virginiana and C. betulus belong to the family Betulaceae. Generally that means wind pollination and non-showy flowers. Both male flowers and female flowers are borne catkins. The male catkins are formed in the fall and overwinter and the female appear in spring. Because the female flowers of both Ironwood and European Hornbeam are each subtended by a large bract, the fruiting structures bear a superficial resemblance to each other. Those of Ironwood, though, are clustered tighter together causing the whole structure to resemble the fruit of hops (hence the other common name). The bracts of Ironwood are also pretty much entire while those of European Hornbeam are three-lobed.
Because Ironwood is a slow-growing, small to medium tree with a maximum height of about forty feet and a spread of about twenty-five feet it is suitable for the smaller landscape and/or street tree use. It needs a moist and well-drained soil that is cool and slightly acidic and it should be planted in the early spring. It is relatively pest and disease free though fungal-induced witches' broom can be a problem. Some references note that this is not a long-lived tree but don't indicate what the typical life span is.
O. virginiana is available from sixteen Ohio nurseries so it shouldn't be too difficult to find.
On a separate note, I must add a caveat to my January article about beautyberry. Leo Mahoney, an adjunct faculty for our program and an employee at the Cleveland Metroparks Zoo tells me that beautyberry can be quite invasive and should be used with caution.
Article and photo by David Emmitt, Program Manager-Plant Science and Landscape Technology, Cuyahoga Community College, Eastern Campus. The program's curriculum is accredited by the Professional Landcare Network (PLANET) and courses taught include botany, woody and herbaceous landscape plant materials and entomology. He received both his Bachelors and Masters degree from Kent State University.
