Blackhaw Viburnum

Size, growth and what to expect

Blackhaw makes a shrub 12 to 15 feet high and 6 to 12 feet across, and an old plant trained to one trunk can reach 30 feet. Expect roughly a foot and a half of new height a year when it is young on an average site, the rate our growth estimator uses for a medium shrub.

Flat clusters of white flowers 4 to 5 inches across open in May and June. The fruit ripens blue-black in September and October, an oval about a third of an inch long that can be eaten off the bush or cooked into jam. Songbirds, squirrels and chipmunks take what you leave. The name black haw refers to its supposed likeness to the hawthorns, which are sometimes called red haws. The mature bark breaks into brown blocks, and the young stems are reddish with a pink bloom.

It grows wild from Connecticut west to Michigan and Kansas and south to Georgia and Texas, in woods, thickets and along streams.

How to grow Blackhaw Viburnum

Blackhaw viburnum takes full sun, part shade or fairly deep shade, on dry to average soil, clay included. It makes a broad, tree-like shrub, so allow 10 feet between plants in a hedge and as much from a wall.

Plant in the dormant season. We ship saplings bare-root or in pots. Dig a shallow hole twice the root spread, keep the crown at the soil line, and refill with native soil rather than compost or peat. Mulch a ring out toward the branch tips, pulled back from the stems. No stake is needed. Seed has a double dormancy. It roots in summer warmth and sends up a shoot only after the next winter. Sow it outdoors in fall, or hold it and sow by early May, and seedlings appear the second spring after you collect it.

Water through the first two summers in dry weather, because blackhaw is slow to settle in. Rabbits clip young stems in winter and deer browse the tops, so fence the plant for two or three years.

Fruit set is heavier with a second, unrelated plant nearby, so put in two if you want the sweet blue-black fruit. It suckers slowly into a thicket. Fall color holds purple-red late, and the fruit hangs on after the leaves drop. Shape it right after bloom, since flowers form on old wood.