Nannyberry can grow into a small tree, but is normally an understory plant of moist woods. In the landscape the plant can be leggy and will send up suckers.
Bark on mature stems is dark reddish-gray to black with a few warty bumps and becoming scaly with age. Young stems can also have a rusty-brown downy appearance. The flower buds that form on the tips of last years twigs are distinctive with a round base with a long pointed spire.
Leaves are shiny dark green above, 2 to 4 inches long, egg shaped with fine teeth and usually pointed at the tip. They are in opposite pairs on the twigs. Newly emerged leaves are downy. Leaf stalks are reddish with small wings. Fall color is a nice maroon.
The inflorescence is a round topped cluster (cyme) 3 to 5 inches across of small 5-parted white flowers. These rise from terminal buds of the prior years growth. The cyme appears with the leaves.
Flowers have 5 protruding stamens with yellow anthers, that are placed alternate to the lobes of the white corolla. The pistil has a short thick green style. The calyx remains green, has five teeth at the tip, which persist onto the fruit.
Fruit: Flowers mature into bluish-black edible oval drupes, about 1/3 inch wide, that hang from reddish stems. The drupes contain a single large stone seed that occupies much of the volume of the drupe. The ripe fruit is eaten by many birds and animals usually after it has frozen and thawed as the fruit then turns sweet. Over ripe fruit smells like wet sheep wool, hence one of the alternate common names of Sheepberry. Humans will find the fruit barely palatable. Cooking has not found it any better.
Habitat: The preferred habitat is moist soil in low woods or swamp borders, but it can tolerate drier sites. The plant is susceptible to damage by the viburnum leaf beetle (Pyrrhalta viburni), but usually the leaves are not bothered by insects (more notes below).
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. The genus Viburnum covers a large number of shrubs and the name is an old Latin name for one particular member of the genus. The species, lentago, comes from another Latin word meaning 'flexible' and was assigned by Linnaeus as the twigs are very tough and flexible. The author name for the plant classification, 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Above and Below: The small 5-part flowers have five stamens with yellow anthers and appear in a rounded top cluster at the end of stems along with the leaf cluster. Leaves are sharply toothed, ovate, with pointed tips.
Below: The flower buds of Nannyberry are in the shape of a round bud with a long-pointed spire at the tips of last years twigs (1st photo). These open (2nd photo) exposing the developing flower cluster.
Below: 1st photo - The green fruit of late June. Note the wings and the reddish color on the leaf petioles. 2nd photo - The color of the autumn leaves shading to maroon.
Below : The mature bluish-black fruit. Note the red stems of the drupes.
Below: 1st photo - Bark of a large mature stem. 2nd photo - The mature drupes contain a large stone seed that takes up much of the volume of the drupe - another reason why picking Nannyberries, irregardless of the taste, does not yield a lot of pulp per quart.
Notes: Nannyberry is indigenous to the Garden area. Eloise Butler catalogued it on April 29, 1907. She also planted some on May 28, 1909 - plants obtained from the Park Board Nursery. It is listed on Martha Crone's 1951 census of Garden plants. Curator Susan Wilkins planted 10 in 2015. The plant is native to many counties in Minnesota with most exceptions being in the SW quadrant and also absent in the Arrowhead. In North America its range is from the east coast westward to Montana, Wyoming and Colorado, mostly absent in the southern states. In Canada it almost reaches Alberta.
Nannyberry is one of six Viburnums found in Minnesota. Four are native - this species plus Squashberry, V. edule; Downy Arrowwood, V. rafinesquianum; and Highbush Cranberry, V. opulus var Americana. 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. V. lentago, Nannyberry, is only moderately susceptible and are usually not destroyed by the pest. [Details in this PDF]
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"