Dr. Dirr

Dr. Dirr's Tree Spotlight: Quercus shumardii - Shumard Oak

Shumard oak is one of the most widely distributed species of the red oak group ranging from Ontario (4 counties) to Florida, west to Kansas, Oklahoma, and Texas. In nature, it occurs on mesic slopes, bluffs, bottom lands, stream banks and poorly drained uplands. A report from Mississippi, indicated good survival and growth on 25-year-old […]

Dr. Dirr's Tree Spotlight: Gymnocladus dioicus-Kentucky coffeetree

An email arrives from a master wood craftsman in Limerick, Maine. It reads… “have access to a giant log of Kentucky coffeetree but am broke. Could you help?” Indeed, I did, based on the beautiful small table he previously designed and built from bigleaf maple, Acer macrophyllum. Cream-colored wood with birds-eye maple-like pattern; a piece […]

Dr. Dirr Spotlight: Pyrus calleryana- Callery pear and invasiveness

Touted as the biological savior for stressful environments since the introduction of ‘Bradford’ in January, 1960. Profuse white flowers in spring, shining dark green summer foliage, turning red to red-purple in fall endeared it to landscape architects, gardeners and nursery producers. It was considered a non-fruiting introduction as the species is self-sterile and requires out-crossing […]

Dr. Dirr's Tree Spotlight: Ulmus americana

Without equivocation, the American elm was the dominant street, shade and urban tree species in North America until the introduction of Dutch elm disease. Embedded in its genome (DNA) is the ability to prosper in wet, dry, acid, alkaline, cold and hot environments. Fast growing, easy to transplant, and guaranteed to survive the salvos of […]

Dr. Dirr's Tree Spotlight: Quercus bicolor

The North American deciduous forest is rich with oak diversity such as Quercus bicolor. Oaks are categorized as belonging to the White or Red /Black groups. The former with rounded lobes or teeth (no bristles), acorns ripening the first year, often scaly bark; the Reds with bristle-tipped leaf lobes, acorns ripening in two years, and […]

Dr. Dirr's Tree Spotlight: Metasequoia glyptostroboides

Dr. Dirr's Tree Spotlight September 18th, 2017 The species, Metasequoia glyptostroboides, was considered extinct until rediscovered in the 1940s in China and reintroduced via the efforts of the Arnold Arboretum, Jamaica Plain, Massachusetts. Seeds and seedlings were distributed to many public gardens and universities with trees now over 100’. Missouri Botanical Garden, St. Louis, houses […]

Dr. Dirr's Tree Spotlight: Aesculus flava

Dr. Dirr's Tree Spotlight: August 28th, 2017 Such a great tree, reaching its zenith in the southern Appalachians, with trees 80 to 100’ in height. Most often found in moist hardwood coves on slopes and along streams, often in the company of mountain-laurel and rhododendron. The species is also common along the Blue Ridge Parkway […]

Dr. Dirr's Tree Spotlight: Corylus fargesii- Farges filbert or hazel

With the loss of Fraxinus, ash, to emerald ash borer and no resistance among the 22 U.S. native species; the uncertainty of long term performance of disease-resistant American elm cultivars; and the invasive issues attached to Norway maple and other species, new tree genetics are necessary. I first witnessed 20 to 30’ high trees at […]

Woody Plant Identification: Utilizing ALL the Senses to Bring Order to Chaos

Always enjoyed TREES and SHRUBS, desired to know their names and learn their characteristics. Reflect to my youth, hunting squirrels with my Dad, collecting Ohio buckeyes (seeds) by the pocketfuls. Quite an easy genus to assimilate. Thirteen species worldwide, all with opposite, compound palmate leaves. Many hybrids within Aesculus thus presenting challenges as to exact […]

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