August 1, 2012 /
Sebastian O'Connor

Tree of the Month: Sourwood

Do you have a taste for honey, an eye for vibrant colors, and a love for trees with a slightly drooping form? Then Oxydendrum arboretum, also known as the sourwood, may be the perfect tree for you!

The sourwood is a lively and bold tree that ranges along most of the southeastern United States, from North Carolina to Arkansas, and West Virginia to the Gulf of Mexico (although it largely bypasses Florida). A member of the Ericaceae (heath) family, the sourwood is a deciduous and slow growing small-to-medium sized tree. Although special cases can occur where the tree reaches 90 feet in the wild, most of the time you will find cultivated specimens no taller than 40 feet.

A special feature of the sourwood is its leaves, which are arranged in spiral or alternate form with an oblong, oval shape. The edges are finely toothed and the upper surface is shiny and smooth and bright green in the summer. Part of what makes the sourwood distinctive is that the leaves droop slightly from their branches, giving the tree a weeping willow-type aesthetic. In the fall, the leaves put on a magnificent show, expressing colors that include a bright crimson red or purplish burgundy. But if you have an urge to take a bite from one of the leaves, be warned that the sourwood is so named because of the very sour and bitter taste of its leaves!

Also contributing to the sourwood’s beauty are its small and delicate, yet showy white flowers that are very fragrant and shaped like a small bell. In July these wonderful flowers come to full bloom and attract a number of pollinators. The nectar from the flowers are incredibly sweet and contribute to a highly-prized honey, which is one of the main commercial uses of the sourwood tree. Oxydendrum arboretum sprouts fruit in late fall consisting of small, hardened capsules that holds many pale brown wingless seeds.

The sweet nectar and sap of the sourwood led to early colonists and Native Americans utilizing it for a variety of things. It was used as a tonic, decoction, and even as a gum; medicinal uses include treating urinary problems, prostrate conditions, diarrhea, dysentery, and many other symptoms. The Oxydendrum arboretum is a little less adaptable to its environment than other urban trees as it is generally intolerant of heavy shade, as well as high soil alkalinity and salinity. It prefers moist, well drained soils with a balanced pH level that are not compacted. On the other hand, although it attracts some nuisance pests, the sourwood is very easy to care for and has no known major diseases.

Its small size and particular growing requirements mean that you will most likely find the sourwood tucked away in public parks and private residences rather than along streets and walkways. In Washington, D.C. you can find examples of this fine tree near the National Cathedral, the Glenwood and Arlington cemeteries, as well as Walter Reed Army Medical Center!

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Photo credit: Mrs. Gemstone.