Blackhaw Plant Care

Blackhaw (Viburnum prunifolium) belongs to the Viburnaceae family within the Viburnum genus. Blackhaw is native to eastern North America, from Connecticut west to eastern Kansas, and south to Alabama and Texas. Blackhaw is also known as Black Haw Viburnum, Sweet Haw, Sheepberry.

Blackhaw displays an upright, spreading shrub growth habit, reaching up to 10 ft tall with a spread of approximately 8 ft. Blackhaw produces clusters of small, fragrant white or pink flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted Blackhaw every 7–10 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Blackhaw thrives in full sun to part shade.

Viburnum prunifolium tolerates temperatures of 0–100°F. Blackhaw prefers humidity levels of 40–70%.

Moist, well-draining loamy soil enriched with organic matter. Good drainage is essential for Blackhaw to prevent waterlogging, which leads to root rot and fungal issues.

Feed Blackhaw every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Choose a spot with full sun to part shade and moist, well-draining loamy soil enriched with organic matter. Avoid low spots where water collects after rain.

Blackhaw is suited to USDA Zone 3a – 9b.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

Blackhaw can spread to about 8 ft (2.4 m) and reach about 10 ft (3 m) tall. Space plants about 8 ft (2.4 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

Prune Blackhaw while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

Blackhaw is hardy down to USDA zone 3a, so once established it can stay outdoors through winter in that zone and warmer ones.

Water deeply in late autumn before the ground freezes, and spread a 5–8 cm (2–3 in) layer of mulch over the root zone, keeping it away from the trunk.

Young and container-grown trees need extra protection: roots in a pot freeze much more easily than roots in the ground.

Blackhaw can be propagated through softwood cuttings, semi-hardwood cuttings, seeds. Similar propagation techniques also apply to mapleleaf viburnum plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Blackhaw is susceptible to aphids, scale insects, viburnum beetles. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

Blackhaw grows outdoors in USDA Zone 3a – 9b. It survives winters down to planting zone 3a. Blackhaw is native to eastern North America, from Connecticut west to eastern Kansas, and south to Alabama and Texas.