Sourwood (Oxydendrum arboreum): Four-Season Native with Lily-of-the-Valley Flowers

Sourwood, also called Sorrel Tree or Lily-of-the-Valley Tree, is a native gem of the eastern U.S. that offers something beautiful in every season. Oxydendrum arboreum (family Ericaceae) is the sole species in its genus, found on acidic, well-drained slopes from Pennsylvania to Florida and west to Louisiana.

Year-Round Ornamental Value

In late spring to early summer, the tree produces 4-10 inch long, gracefully arching panicles of white, urn-shaped flowers—strikingly similar to lily-of-the-valley—with a light fragrance. The flowers are a major nectar source for bees (producing prized sourwood honey). The leaves are alternate, simple, 4-8 inches long, finely toothed, glossy green, turning brilliant crimson, purple, and scarlet in fall—among the most spectacular fall color of any native tree. The bark is gray-brown, deeply furrowed and blocky with age. The seed capsules persist into winter.

Taxonomic Classification

Culture and Landscape Use

Sourwood requires acidic (pH 4.5-5.5), moist, well-drained, organic soil—conditions similar to azaleas and blueberries. It fails in alkaline or compacted clay. It prefers full sun to partial shade (best flowering in sun, best fall color with some shade). It's slow-growing (12-24 inches/year) to 25-30 feet tall, with a narrow, pyramidal to oval crown.

It's difficult to transplant (taproot); plant container-grown, young specimens. Mulch well to maintain soil moisture and acidity. It's relatively pest-free. In the landscape, it's a superb specimen tree for woodland edges, native plant gardens, and acidic sites where its four-season beauty can shine. The honey is a regional delicacy—light, aromatic, and slow to crystallize.