Black Haw Viburnum Plant Profile

Rusty blackhaw viburnum white flowers on green shrub
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The black haw viburnum is a species of viburnum shrub that can also be trained to grow like a small tree. It features abundant clusters of snowy white flowers called "cymes" that bloom in the spring. After the flowers are fertilized and fade away, black fruits, known as "drupes," form and ripen by fall. They're edible for both humans and wildlife. Some other distinctive features include the bark, which resembles alligator skin, and the fishbone pattern formed by the branches.

The scientific name for this shrub is Viburnum prunifolium, and it's part of the Adoxaceae family. The species name of prunifolium indicates that the leaves are similar to those of Prunus trees and shrubs, especially plums. The leaves are oval-shaped, dark green, and grow up to four inches long. In the fall, the foliage will transform into shades of red and purple.

Growing Black Haw Viburnum
Botanical Name Viburnum prunifolium
Common Name Black haw, stag bush, blackhaw, or sweet haw
Plant Type Perennial shrub
Mature Size 15 feet tall and 12 feet wide
Sun Exposure Full sun to partial shade
Soil Type Any type, well-drained
Soil pH Any
Bloom Time Spring
Flower Color White
Hardiness Zones 3–9
Native Area  Eastern and Midwestern United States

How to Grow Black Haw Viburnum

Black haw viburnum is a low-maintenance shrub that grows well in many different locations and climates. Early spring and fall are ideal times to plant, and a spot with well-drained soil and ample sun will get you the best results. You can mix in some manure or compost into the soil before planting, and top with mulch to help improve the drainage. These shrubs can become quite large, so make sure there's enough space for it to expand.

Black haw viburnum is very hardy—it's able to tolerate the juglone produced by the black walnut and other walnut tree species. This substance is allelopathic and will harm many other plants, so planting a black haw bush nearby is a good choice. These shrubs will also withstand pollution in urban settings.

Butterflies, bees, and birds are all attracted to black haw flowers. And if you want a shrub with leaves that turn a vibrant red in the fall, look for 'Ovazam', 'Forest Rouge', 'Summer Magic', or 'Early Red' cultivars.

Light

Choose a site for your black haw that will provide full sun to partial shade. It can also handle a spot with more shade, though there may be fewer flowers and fruit.

Soil

Good drainage is necessary for this shrub, and it can tolerate most pH levels. It prefers loamy soil, but it does grow in clay and sandy areas.

Water

When you first plant your shrub, you'll need to water it at least every other day until it takes root. Once established, it will require minimal watering unless you experience long periods of heat and drought. 

Temperature and Humidity

Black haw viburnum is tolerant of hot temperatures of over 90 degrees Fahrenheit as long as it has enough water. It will also survive in conditions dipping well below freezing during the winter.

Fertilizer

Your black haw bush will benefit from a seasonal feeding in the spring. Spread a 10-10-10 granular fertilizer mix at the base of the plant, creating a circle with a 3-foot circumference.

Propagating

You can propagate black haw by germinating the seeds. Save seeds by harvesting the fruit once it turns black, and drying the berries (with pulp) in a cool location. Once dry, store the seeds over the winter in a brown paper bag. Plant them in small pots in early spring, and then transplant them outdoors when the plants become large enough, around one foot tall.

Pruning

You can make a black haw viburnum into a small tree through pruning to create a central leader. It can also be trained into an informal hedge for use as a privacy screen. The shrub may sometimes clone itself through suckers that will need to be detached to keep it under control.

To avoid removing the buds for the next year's blooms, pruning should be done right after flowering has finished.

Common Pests and Diseases

While there aren't usually many pest or disease problems with black haw viburnum, you may experience the following issues:

Pests

  • Scales will suck the sap out of the stems. Horticultural oil can be used on cool days to help fight the infestation.
  • Borers will attack the trunk by burrowing through the bark to the inner layers. It may be difficult to get rid of the beetles, and if the damage is widespread, it can lead to the death of the shrub.
  • Aphids can cluster on the shrub. You can spray them with water or use an insecticidal soap or horticultural oil. The latter two treatments should be used only on cooler days, so the leaves of the shrub do not get burned. You can also control any ants in the area as they will care for the aphids in exchange for their honeydew.

Diseases

  • Powdery mildew can be treated with organic methods like a baking soda solution, water spray, or neem.
  • Cankers (dead sections of bark on branches) should be pruned while they're still small. If they're large, you may eventually need to take out the whole shrub.
  • Dieback happens when parts of the plant start to wither, and the damage spreads throughout the entire shrub over time.