The Viburnums are shrubs of woodlands and moist woodland borders. The Highbush Cranberry is a native tall shrub, reaching to 15 feet in height, with arching multiple stems.
Twigs are a light reddish brown and have opposite buds with reddish- brown scales.
Bark on older stems becomes gray and scaly.
The leaves are opposite, simple three lobed and with course teeth and 1 to 6 small glands, on short stalks, near the base of the blade on the grooved reddish-brown stalk. The leaves are green during the summer and turn to a nice purplish-red in Autumn. The undersides are hairy. There is a pair of slender stipules where the stalk attaches to the stem, but these drop away early. The groove on the stalk is wide and flat-bottomed.
The inflorescence consists of flat-topped clusters of stalked flowers (a cyme), each cluster up to 3 to 4 inches wide, on the tips on new growth.
The flowers are of two types - an outer ring of florets that are particularly showy and noticeable. These are sterile, whereas the inner cluster of small florets are fertile. The corollas are white, 5-parted. The outer florets have corollas with 5 spreading rounded lobes, a short green calyx with 5 pointed lobes. The inner florets are similar in shape but only 1/4 inch wide. These have the reproductive parts of 5 stamens that have white filaments and creamy colored anthers and which are exserted from the corolla. These are spreading and placed alternate to the petals. The pistil and ovary lack a style.
Fruit: After flowering in May the fruit forms and gradually changes color from green to the deep red of Autumn. Each drupe is about 1/3 inch across and contains one flattened 5mm wide seed. The fruit is acidic but edible off the plant and when properly prepared makes a good preserve.
Habitat: Highbush Cranberry prefers the consistently moist soils of low places as long as the soil is loamy with drainage, and it needs plenty of sun to flower and fruit sufficiently. Pruning is best done immediately after flowering. The majority of these shrubs in the Woodland Garden of Eloise Butler are found near the Mallard Pool, are quite old and produce quantities of berries.
Names: In the never ending quest for specificity, botanists have recently moved the Viburnum genus into the Adoxaceae plant family, which is a small group of 5 genera of shrubs that have opposite leaves, mostly 5-petaled flowers that produce a small drupe. Minnesota authorities have made this change, USDA has not yet. Botanists have also recently reclassified the species of this plant from the old Viburnum trilobum to a variety with the name Viburnum opulus var. americanum. Interestingly, in Eloise Butler's time the plant was known as V. opulus var. americanum. The genus name, Viburnum, covers a large number of shrubs and the name is an old Latin name for one particular member of the genus. The species opulus, is taken directly from the Greek where it referred to a type of maple and was applied here due to the maple-like leaf shape. The author name for the plant classification, ‘Aiton’ is for William Aiton (1731-1793), Scottish botanist, who succeeded Phillip Miller as superintendent of the Chelsea Physic Garden and then became director of Kew Gardens, where he published Hortus Kewensis, the Garden’s catalogue of plants.
Comparisons: While there are other Viburnums in Minnesota as denoted below, the one closely resembling this species is the introduced European Cranberrybush, V. opulus var. opulus. The European variety grows in more upland sites but does hybridize with the American variety. The tiny glands on the leaf stalk are usually sessile. The groove on the leaf stalk is narrow with a v-shaped bottom. A fairly complete review of both species is found in this Technical Conservation Assessment (pdf) from the USDA Forest Service.
Above: 1st photo - Flowers of late May. The sterile florets form the outer ring. 2nd photo - Green fruit of mid June. 3rd photo - Ripe berries of Autumn
Below: 1st photo - the fertile florets are in the center of the cyme. 2nd photo - The twigs have opposite buds that are reddish in color.
Below: The simple, three-lobe opposite leaves. Note the small glands on the base of the leaf at right.
Below left: 1st photo - At the base of each leaf is a pair of thread-like stipules. 2nd photo - On the grooved leaf stalk at the base of the leaf are from 1 to 6 (4 here) stalked oil glands. 3rd photo - Bark on older stems becomes gray and on really old stems, scaly but you seldom see old stems that large.
Below: The underside of the leaf is a paler color with fine surface hair - longer hair on the veins.
Below: A typical cyme with the outer ring sterile florets open and the smaller inner fertile florets still in bud.
Below: A group of Highbush Cranberry in flower in the Woodland Garden. The plant makes a good yard specimen where it can be left to grow naturally or slightly pruned to a shape. The plant is dense due to its many stems but it forms a clump and does not form thickets or send up suckers. Pruning of a landscape specimen should not be necessary but like lilacs, several old stems should be removed each year to generate new growth from the base and this is done immediately after flowering.
Notes: Highbush Cranberry is indigenous to the Garden area. Eloise Butler catalogued it on April 29, 1907. Her records also show that she planted this species on April 14, 1910 with plants obtained in Lake City, MN; again on May 1, 1910 with a plant from Cokato, MN; on June 4, 1919 from Northrup King (A seed and plant provider); and in Oct '19 a plant from Meadowbrook on the Luce Line RR. Martha Crone planted 12 in 1945, more in 1947 and '57. Curator Susan Wilkins added additional plants in 2008. It is native to most Minnesota counties except the SW quadrant. In North America the plant ranges across the entire northern part of the continent except the arctic provinces. In the U.S. It grows as far south as Nebraska and Kentucky.
Highbush Cranberry is one of six Viburnums found in Minnesota. Four are native - this species plus Squashberry, V. edule; Downy Arrowwood, V. rafinesquianum; and Nannyberry, V. lentago. Two are introduced - European Cranberrybush, V. opulus var. opulus, and Wayfaring-tree, V. lantana. Another Virburnum that will grow nicely in Minnesota, but is not native to the area is Southern Arrowwood, V. dentatum.
Pests: Viburnums are subject to damage from the Viburnum Leaf Beetle, Pyrrhalta viburni, a native of Europe, which first was found in North America in 1947. The larvae feed on the leaves. Female beetles hollow out an egg cavity on the twigs to hold their eggs which over-winter and hatch in the spring. Certain species of Viburnum are more susceptible that others to the pest with V. dentatum, V. rafinesquianum, V. nudum, and V. opulus var. americana being most susceptible. These species will succumb to the pest in 2 to 3 years of infestation unless the eggs are destroyed. For just a few plants, cut off twigs with egg cases in late fall after the beetles have died. [Details in this PDF]
Winter Interest: Plants will many times hold their red fruit well into the winter, making a strong contrast with winter grays and whites. Many birds prefer to eat the berries after they have been once frozen and thawed, which reduces the acidic content
Medicinal Lore: The bark of V. opulus has been used as a pharmacological ingredient for the relief of cramps and spasms. It was listed in the both the U. S. Pharmacopoeia and in the National Formulary. The dried bark of the stem would be steeped in boiling water, then mixed with other natural ingredients and taken as a tonic. The glucoside Viburnine is the active principle. See Hutchins (Ref. #12) for more details.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"