Viburnums are found in North and South
America, southeast Asia, and the Atlas Mountains of Africa. There are over 150 species. Previously,
viburnums were classified as part of the honeysuckle (Caprifoliaceae) family. Based on the results of DNA sequencing, they have recently been re-classified as part
of Adoxaceae, which also includes elders and several herbaceous plants.
Identification: Viburnums are robust shrubs, or occasionally small trees,
usually with multiple stems and branches. Leaves are variously shaped, often with serrated edges and
prominent veins. The flowerheads have flat tops.
Many of these plants are hermaphrodites—the flowerheads contain both a ring of
sterile, larger flowers as well as a central region composed of smaller, fertile flowers. Flowers are white, cream-colored,
or pink, with five petals. The flowerheads become
clusters of brightly colored berries.
Guelder rose (Viburnum opulus) · 9/13/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 9 × 6″ (23 × 15 cm)
Shrubs are 4-6′ (1.2-1.8 m) tall and 3-4′ (91-121 cm) around.
Densely-branched shrub 6-10′ (1.8-3 m) around.
Irregular bush 6-12′ (1.8-3.7 m) high.
Flowers
White flowers are in ball-shaped, flat-topped, or spike-shaped clusters. Individual flowers are less than ¼″ (6.3 mm) across.
Cream-colored corymbs 1-4″ (2.5-10 cm) across, with tiny flowers about ⅛″ (3.2 mm) across.
Flowerheads up to 5″ (12 cm) across, with a central region with fertile ⅛″ (3.2 mm) flowers edged with ¾″ (1.9 cm) sterile white-to-pink flowers, each with five petals.
Leaves
Leaves are dark green, three-lobed, 2-4″ (5-10 cm) long, occurring in opposite pairs. Their maple-like leaf shape distinguishes this species from other viburnums.
Often shiny, roughly oval, toothed, strongly textured and veined, somewhat rough to the touch, and 2-4½″ (5-11 cm) long.
Heart-shaped, prominently veined, 4-8″ (10-20 cm) long, with serrated edges.
Stem
Bark is gray-brown and warty, later becoming furrowed.
Fruit
Berries go from green to red to blue-purple to almost black in color; they are about ¼″ (6.3 mm) around.
Blue-black berries ¼″ (6.3 mm) in diameter, in flattened clusters.
Oval berry clusters are first red, ripening to black.
Large, often irregular shrub or small tree up to 30′ (9 m) tall, but usually 12-15′ (3.7-4.6 m).
A shrub 13-16′ (4-5 m) around.
These shrubs are 8-10′ (2.4-3 m) tall and usually somewhat wider than they are tall, and densely branched. Branches are distinctly layered.
Flowers
Flowerheads are cream-colored, flat-topped, up to 5″ (12 cm) in diameter.
Flowerheads are 1½-4″ (4-11 cm) around. Each head has an outer ring of sterile, white- or cream-colored flowers ½-¾″ (1.5-2 cm) around, with five petals. Within this ring is a large number of very small, fertile flowers, also white, about ⅛″ (5 mm) around.
White, up to 4″ (10 cm) in diameter, in the form of flat flowerheads, with an outer ring of infertile flowers about ½″ (1.3 cm) around and an interior region filled with ⅛″ (3.2 mm) fertile flowers.
Leaves
2½-4″ (6.3-10 cm) long, medium- to dark green, shiny, roughly oval to elliptical in shape, with serrated edges.
Three-lobed, coarse-veined, somewhat maple-like leaves 1¾-4″ (5-10 cm) in size. Leaves have course serrations, and occur in opposing pairs.
Roughly oval-shaped, rounded at the bottom and pointed at the top, 2-4″ (5-10 cm) long and 1¼-2″ (3.2-5 cm) wide, with serrated leaf edges. In the fall, leaves are dark reddish purple.
Stem
If it has a single trunk, it is up to 10″ (25 cm) in diameter. Multiple trunks are smaller.
A shrub or small tree, 15-20′ (4.6-6.1 m) high (rarely 30′ (9.1 m)) and 10-15′ (3-4.6 m) around. It is rounded but fairly sparse.
Flowers
Flowerheads have many tiny white blossoms.
Leaves
Leaves occur in opposing pairs, 2-6″ (5-15 cm) × 1½-3″ (3.8-7.6 cm), with serrated edges and prominent veins. Sometimes the leaves become red or purple in the fall.
