Viburnum opulus

Viburnum opulus, commonly known as the guelder-rose, or guelder rose (/ˈɡɛldər/), is an Old World species of flowering plant in the family Adoxaceae.

Viburnum opulus is a deciduous shrub growing to 4–5 m (13–16 ft) tall. The leaves are opposite, three-lobed, 5–10 cm (2–4 in) long and broad, with a rounded base and coarsely serrated margins; they are superficially similar to the leaves of some maples, most easily distinguished by their somewhat wrinkled surface with impressed leaf venation. The leaf buds are green, with valvate bud scales.

The hermaphrodite flowers are white, produced in corymbs 4–11 cm (2–4 in) in diameter at the top of the stems. Each corymb comprises a ring of outer sterile flowers 1.5–2 cm (5⁄8–3⁄4 in) in diameter with conspicuous petals, surrounding a center of small (5 mm or 1⁄4 in) fertile flowers. The flowers are produced in early summer and are pollinated by insects. The fruit is a globose bright red drupe 7–10 mm (1⁄4–3⁄8 in) in diameter, containing a single seed. The seeds are dispersed by birds.

Its fruit persists for an average of 200 days, and always bears 1 seed per fruit. Fruits average 88.0% water, and their dry weight includes 17.3% carbohydrates and 1.3% lipids.

The common name 'guelder rose' relates to the Dutch province of Gelderland, where a popular cultivar, the snowball tree, supposedly originated. Other common names include water elder, cramp bark, snowball tree, common snowball, and European cranberrybush, though this plant is not closely related to the cranberry. Some botanists also include the North American species Viburnum trilobum as V. opulus var. americanum Ait., or as V. opulus subsp. trilobum (Marshall) Clausen.

Viburnum opulus is a member of the Viburnum genus which contains 160 to 170 species. It is classified in the subsection Opulus, which usually contains five species. Phylogenetic analyses suggest the following relationship between those species:

The species is native to Europe, northern Africa, and central Asia. It is naturalised in North America.

Viburnum opulus is grown as an ornamental plant for its flowers and berries, growing best on moist, moderately alkaline soils, though tolerating most soil types well. Several cultivars have been selected, including 'Roseum', in which all the flowers are only of the larger sterile type, with globular flower heads.