Any woodland border gains instant status with the addition of this resplendent American native wildflower.
Giant Solomon’s seal (Polygonatum biflorum var. commutatum) is native to the eastern U.S. and south-central Canada and hardy from zones 3 to 7. This shade lover typically grows in the fertile loamy soil of woodlands in light shade to partial sun. Giant Solomon’s seal is dramatic and refined at the same time. The leaning stems of mature specimens can grow from 3 to 7 feet, with taller heights being reached under optimal conditions. Because of the graceful arch of its stem, a single plant might reach from 3 to 4 feet across. The closely spaced dark green leaves may be up to 6 inches long and 4 inches across. From May to June the plant produces umbels of three to ten tiny flowers which dangle beneath the leaves. By summer the whitish green flowers turn to bluish-black berries that are relished by birds. Come fall, the leaves take on a mellow golden hue. A grouping of giant Solomon’s seals is particularly striking in early autumn, when the plants rustle and dance in the wind on stems that remain strong until felled by frost.
Close examination of the giant Solomon’s seal reveals many similarities to its diminutive relative, lily of the valley (Convallaria majalis). Despite the difference in their sizes, both of these woodland-dwelling spring bloomers produce gently arching stems beneath which are suspended tiny bell-like flowers. Both also tend to grow into colonies.
This plant’s scientific nomenclature is somewhat confusing. It is often listed as P. biflorum var. commutatum, but you may also find it called P. commutatum, P. canaliculatum or P. giganteum as well. Some sources attribute giant Solomon’s seal to the Ruscaceae family, but the USDA classifies it as part of the Liliaceae family.
The plant’s common name of Solomon’s seal derives from its rootstock, which bears flat round scars that resemble the impression of a seal. One of history’s most famous seals, of course, was a magical signet ring said to belong to the biblical King Solomon. A transverse cut on the root was once believed to reveal Hebrew characters left by the wise king’s seal. You can estimate the age of a Solomon’s seal plant by counting the scars, since each year of growth leaves a new “seal” on the rhizome.
Giant Solomon’s seal is a rugged deer-resistant plant largely unbothered by disease. It prefers a cool moist soil, but will tolerate either dry or damp soil once established. Planted in a spot to its liking, this perennial really asks for nothing except plenty of room to expand its luxurious arching stems. No deadheading is necessary -- the flowers drop off on their own, and you don't want to lose the berries that take their place. To create new plants, you can divide larger clumps in the spring or early in the fall. Plant rhizomes only a couple of inches deep and about 2 to 3 inches apart in rich, organic soil. Wherever you plant them, give these plants adequate space, both to send their arching stems outward and to spread into a colony. New plants may be somewhat slow to take off but will eventually naturalize.
Solomon's seal was part of the native American pharmacy as well. it is mucilaginous, which means the sap is soothing for burns and sore throats. The sap was especially helpful for dry coughs and lung ailments. Modern research has validated these practices and there are several commercial herbal products on the market today.
Good companions for the giant Solomon’s seal include other shade denizens such as ferns, hosta, pulmonaria, brunnera, dicentra, hellebore, heuchera and tiarella. The stems' arches create a pleasing natural frame when they are allowed to dangle over shorter plants or groundcovers with interesting foliage such as Lamium ‘Pink Pewter’.
Giant Solomon’s seal has a number of shorter relatives, including smooth Solomon’s seal or sealwort (P. biflorum). Also an eastern American native, this Solomon’s seal variety reaches a length of only 1 to 3 feet, with a spread of 1 to 1 1/2 feet. Bloom time is about a month earlier than the giant form.
If you don’t have room for the giant variety, consider planting the lovely variegated Solomon's Seal (P. odoratum var. pluriflorum 'Variegatum') , or pair the two. The variegated Solomon’s seal is a much more delicate plant, reaching a height of 2 to 3 feet with a spread of 1 foot or under. Its soft green leaves edged with cream light up a shade garden all season long. As a bonus, from April to May this plant produces sweetly scented white flowers that hang in pairs from the stem. The variegated form is far shorter than its big relative, so place it closer to the front of the border.
Cornell University: Great Solomon's Seal
Photos courtesy of PlantFiles