Southern Black Haw

Southern Black Haw – Viburnum rufidulum

Southern Black Haw foliage

Family Adoxaceae. Also called rusty blackhaw, bluehaw, rusty nannyberry. USDA hardiness zones: 5B through 9

A native of the well-drained, upland woods of southeastern North America, Rusty Blackhaw forms a multiple or single-trunked small tree or large shrub, reaching 25 feet in height with an equal spread. Trunks usually grow no thicker than six inches and arch away from the tree, forming a pleasing, vase-shaped crown. Leaves are dark green, three inches long, leathery, and extremely glossy.

The tree is covered in springtime with striking five-inch-wide clusters of small, white blooms. These flowers are followed by clusters of dark blue, waxy, one-half-inch-long fruits that are extremely popular with wildlife and will occasionally persist on the plant from September throughout the autumn. In fall, Rusty Blackhaw puts on a brilliant display of scarlet red to purple foliage.

Rusty Blackhaw will grow and look nice in full sun or partial shade on any reasonably fertile, well drained soil. The tree grows in a shady spot but forms a more open habit. Flowering is significantly reduced in the shade. although tolerant of drought, it will not tolerate compacted soil. This would be a good tree for planting beneath power lines and in other limited space areas. Useful as a hedge, specimen, or border tree, this deciduous tree adapts well to urban areas.

Height: 20 to 25 feet / Spread: 20 to 25 feet / Crown uniformity: irregular outline or silhouette / Crown shape: vase shape / Growth rate: slow.

Southern Black Haw Bark

This tree is usually pest-free. Viburnum aphid is gray to dark green and feeds in clusters at the tips of the branches, causing leaf curl. Viburnum opulus is especially susceptible. The insects can be dislodged with high pressure water spray from the garden hose. Inspect the stems of unhealthy-looking plants for possible scale infestations. If found, spray with horticultural oil for some control.

Bacterial leafspot causes round, water-soaked spots on leaves and young stems. These develop into shrunken, brown areas about 1/8-inch in diameter. Destroy infected leaves, if you wish. This is not a problem to be concerned about. Bacterial crown gall forms galls on the lower stems. Do not replant in the same spot. Shoot blight causes grayish to brown decayed spots on the leaves. The spots first appear at the leaf margins, then spread to the rest of the leaf. Infected flower clusters or twigs are killed. A number of fungi cause leaf spots. Rake up and destroy infected leaves. These are usually not a serious problem. Powdery mildew causes a white powdery growth on the leaves, but this Viburnum is usually not affected [4].

1. Edward F. Gilman and Dennis G. Watson, Univ of Florida ENH-819/ST662 Siebold Viburnum
2. Wikipedia, the free encyclopedia, Viburnum
3. The Arbor Day Foundation, Viburnum
4. USDA, ARS, National Genetic Resources Program.  USDA Fact Sheet ST-661 October 1994

Family Adoxaceae. Viburnum is a genus of about 150-175 species of shrubs or small trees that were previously included in the family Caprifoliaceae.
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