This article is republished with permissions from the January 2020 issue of Washington Gardener, a publication covering Washington D.C., Maryland, and Virginia area gardens.
If you’ve read any of my past diatribes, you know that I favor scientific, botanical nomenclature above “common names”. That’s caused many of my readers to come to think of me as a know-it-all. Not the case! But, I’m going to save the plant name discussion for a later date. I just want to inform you that I have no problem with common names, although sometimes they don’t tell you anything about the plant or don’t seem to make any sense.
Well, here’s a definite exception to that rule: Polygonatum canaliculatum, otherwise known as ‘Giant Solomon’s Seal’, a remarkable plant that’s native to every state in the U.S. aside from eight Western states. This plant is a giant in more ways than its size.
Comparing Varieties of ‘Solomon’s Seal’
If you’re not familiar with this plant, I’ll bet you know its “little” cousin, Polygonatum biflorum, the ‘True Solomon’s Seal’, native to the same geographic area. That common name distinguishes it from Maianthemum racemosum, formerly Smilacina racemosa, or the ‘False Solomon’s Seal’. I’m not fond of that common name — if you have to use a common name, try ‘Solomon’s Plume’.
Polygonatum is a genus of plants that has a hard time with familiar relationships. I always knew it as a member of the Liliaceae (lily) family; now, depending on who you’re talking to, it could be in the Convallariaceae or Asparagaceae family.
This story is starting to get away from me, so let’s get back to Polygonatum canaliculatum and talk about the differences between these two kinfolk. Typically, Polygonatum biflorum (biflorum because it produces two flowers at each axil) grows from about 12 inches to 36 inches tall, depending on age, soil fertility, moisture, etc. It flowers from May to June with a graceful, arching stem. On the underside of the stems, in most of the axils, two greenish-white, pendulous, bell-shaped flowers are produced. These flowers turn to blue-black berries over the growing season.
Polygonatum canaliculatum is quite similar in most respects but looks like Polygonatum biflorum on steroids! It typically grows on road banks and is normally 36 to 72 inches, but we’ve had some attain heights of over 96 inches. There are also two to 10 flowers in each axil as opposed to only two in Polygonatum biflorum.
Growing and Using ‘Solomon’s Seal’
For growing. Both plants are easy to grow and propagate. The rhizomes produce a new joint every year and if you dig them up every few years, you can easily multiply them. You can also easily grow them from seeds: just wash the pulp away under running water and sow them outside. It takes several years to raise a mature plant from seed. In the garden, Giant Solomon’s Seal is a welcome guest, there are a multitude of shade-loving plants that you can plant under it. I’ve even planted Polygonatum biflorum under the Polygonatum canaliculatum. The richer the soil, the more organic matter and moisture, the more robust they’ll grow.
For healing. The name of the genus, Polygonatum breaks down as follows: Poly means “many” and gonu means “knee joint”, a reference to the joints on the rhizome. The common name of “Solomon’s Seal” is usually thought to refer to those “knee joints” on the rhizome, but there has been some older writings found to indicate the “Solomon’s Seal” refers to the wound-sealing properties of the rhizome. The specific epithet, canaliculatum means “grooved” or “channeled”, in reference to the grooves on the leaves. Members of this genus have a multitude of other medicinal uses and have been used for the treatment of indigestion, profuse menstruation, lung ailments, general debility, and other ailments. It is a folk remedy for piles, rheumatism, and skin irritations. A poultice or a decoction of the fresh roots is applied to cuts, bruises, and sores.
For eating. The starchy, edible rhizomes were consumed by Native Americans who shared them with the early settlers.
Giant Solomon’s Seal has a place in every shade garden, native plant garden, wild garden, and I’ve even seen them used in rain gardens — where will you grow yours? Use your imagination.
Barry Glick, a transplanted Philadelphian, has been residing in Greenbrier County, W.V., since 1972. His mountaintop garden and nursery at Sunshine Farm & Gardens is a mecca for gardeners from virtually every country in the world. Barry writes and lectures extensively about native plants and Hellebores, his two main specialties, and welcomes visitors with advance notice. Reach Barry at email@example.com and 304-497-2208. Read all of his MOTHER EARTH NEWS posts here.
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