Culture
Best grown in acidic, moist, organically rich, well-drained soils in full sun. Tolerates part shade, but with somewhat diminished flowering and fall color. Intolerant of drought. Intolerant of urban pollution.
Noteworthy Characteristics
Oxydendrum arboreum, commonly called sourwood or sorrel tree, is a deciduous understory tree that is native to the eastern United States from Pennsylvania south to Florida and Louisiana. It is perhaps most commonly found on rocky wooded slopes in the Appalachian Mountains, often growing in combination with other heath family members (e.g., azaleas and rhododendrons) that share the same acidic soil preferences. In cultivation, it typically grows 20-25’ tall with a straight, slender trunk and narrow oblong crown. In the wild, it may reach 50-60’ tall. Gray bark on mature trees is fissured, ridged and scaly. Finely-toothed, glossy green leaves (to 5-8” long) are reminiscent of peach. Leaves have a sour taste, hence the common name. Leaves produce consistently excellent fall color, typically turning crimson red. Waxy, lily-of-the-valley-like, white flowers bloom on slender, drooping, one-sided terminal panicles (4-8” long) in early summer. Flowers have a slight fragrance. Flower panicle stems remains in place as the flowers give way to 5-parted dry capsules that ripen to silver-gray in September. Capsules contrast well with the red fall color and provide continuing ornamental interest after leaf drop into winter. Flowers are quite attractive to bees. Sourwood honey is a highly prized local product.
Genus name comes from the Greek words oxys meaning acid and dendron meaning a tree. The foliage is bitter.
Specific epithet comes from the Latin word arboreus (of a tree).
Problems
No serious insect or disease problems. Leaf spot and twig blight infrequently occur.
Uses
Beautiful small specimen flowering tree with multi-season interest for lawns, patios, shade gardens or open woodland areas.