SOLOMON'S SEAL

Polygonatum (Solomon's seal) is a spectacular and underutilized ornamental plant. The genus, derived from ancient Greek and meaning "many knees," refers to the joints on the thick and fleshy rhizome from which the "stems" are borne. The basis for the common name is uncertain but the usual explanation is that the depressions on the knotty rhizomes resemble a royal seal and King David's successor Solomon was chosen for some reason. The depressions are leaf stalk scars (see pic above, of P. biflorum). Notice also that the pic shows four years of growth and, at the L end, the terminal bud which will produce the next year's "stem." Realize too that several other closely related genera are also occasionally referred to as Solomon's seal (i.e., Disporum, Disporopsis, Smilacina and Uvularia). Moreover, Polygonatum was formerly lumped in the large and unwieldy family Liliaceae. We now know that Polygonatum is a close relative of asparagus, in fact it is in the same family (Asparagaceae) and is also closely related to lily-of-the-valley.

Worldwide there are about 80 Polygonatum species, most of them endemic to Eurasia. The species most commonly available in commerce are Polygonatum biflorum, P. humile and P. odoratum. The last one is the species you will likely see at the garden center. There are 20 or so cultivars of this Eurasia native but, unlike the name suggests, it is only slightly fragrant, certainly not pervasive. The diminutive Polygonatum humile is native to Asia. The North American natives P. biflorum and P. pubescens are good ornamentals but do not have the variation one can find with P. odoratum. -- This is where I usually make a comment about how many native plants zealots are delusional and hidebound :) Native has a different meaning in an ornamental or garden context -- manmade, therefore not natural, and likely to show both form and behavioral variation since often absent associates and forced to grow in an unfamiliar and often unsuitable substrate/site.

Solomon's seal has a stunning and unique look, something like a fern, featuring simple, smooth and entire but captivating leaves. The vegetation, the "fronds," if you will, can be special and there are numerous cultivar forms -- most of them with some sort of variegation. For the taller species and forms I find the flowers and especially the fruits magnificent. The bell-shaped, pendent flowers are typically paired, occasionally solitary, and sometimes more for certain species/cultivars. Furthermore, the tips of the tubular flowers may be flared in some. The flowers are white to cream, with some species/cultivars terminally green or otherwise pigmented. Flowers are produced in late spring, hanging lined up on most of the length of the "stem." The flowers are followed in mid to late summer by fruits about the size of a blueberry and which, like blueberries, start out green and mature to a dark blue to black. But, unlike blueberries, the Solomon's seal fruit is poisonous. By the way, the bright red fruit produced by female asparagus plants are poisonous, too. I find the substantial dangling Polygonatum fruit one of the joys of a late summer garden -- their weight can cause the stocks / "stems" to bend. By the way, the leaves turn a nice yellow in autumn. I remove the spent and fallen "stems" by the following spring. I wait until spring to give the stems time to naturally and completely separate from the rhizome thus not risking dislodging or even unearthing the rhizome.

But, like with any plant, none of the interesting attributes should entice you to plant it in your garden if lacking the appropriate habitat. The plant does best in cool locations with dappled light but they do not like wet conditions and appreciate a thin layer of mulch or compost. Avoid full sun, especially sites with hot afternoon sun -- an absolute no-no as are low periodically inundated woods and suburban sites lacking aboriginal soil. A woodland, especially cove or hollow like conditions with well-drained humusy soil is perfect for Polygonatum. The rhizome is shallow, about the diameter of a finger and taper somewhat towards the growing tip. The shallowness of the rhizomes means you need to be careful cultivating with tools. Note that botanically the rhizome is the actual stem -- they have nodes and buds which are absent in true roots (see pics). The portion that grows upwards and from which the leaves, flowers and fruits are borne is referred to as a stalk or shoot. Moreover, the plants will form a stand or colony and they will move around a bit. This running migration varies by species but, while easy to grow, Polygonatum is NOT a garden thug like some other plants, both native and exotic. Again, the rhizomes are shallow, only a couple of inches deep. Getting new plants is best done by dividing the rhizomes. The division can be done anytime of the year and I find it best to lift and divide the plants every 5-10 years in order to keep them where I want them (i.e. from moving too far) but an unground barrier can impede the movement. When doing so you discover that the cut section behind the eye will not produce a new shot until the year after planting. Further, the trailing portion of the rhizome is the stored food source. Notice in the above pic that the stalk arises from behind the growing tip and if you cut too much away you will stunt this year's growth of the eye. It should go without saying that the eye needs to be planted oriented up. One can also grow new plants by seed but it is easier, and perhaps better, to use an entire berry and the berry should not be allowed to dry before planting. When attempting to propagate by seed, like with the rhizome sections, you will not get aerial growth until after the next year -- seems the seeds need double stratification. The delay in getting new plants to flowers turns off those people needing instant gratification -- it is a large cohort. I have commented many times that patience is a virtue, the lack of which precludes many from gardening.

Again, Polygonatum is one of my favorite herbaceous perennial plants (i.e., forbs) and is vastly underutilized The arching plants, which depending on species, can be as much as 2-5+ feet tall, are uniquely beautiful and more or less disease and pest free, although they do not tolerate long periods of desiccation. They are a perfect complement in a hosta garden. Curiously, Solomon's seal and hosta are closely related. I have taken to using Solomon's seal to adorn the beds at the base of large trees. I leave an apron of vegetation about three feet deep encircling large open grown trees at my place and make sure to extract any woody weeds that start there, and they will, especially vines, but otherwise largely let Nature help me populate the ring. I find these apron beds are perfect for some late season asters, sedges (esp. Carex jamesii) and 'Painter's Pallete,' the gorgeous variegated form of the aggressive and ubiquitous native Polygonum (Persicaria) virginiatum (Jump seed or Virginia Knotweed). The shorter and dwarf forms of Solomon's seal (e.g., P. humile), which are typically six or so inches tall, can be used as a ground cover. The taller forms are perfect as a path or bed edger, especially if elevated, where the flowers and fruit can be more easily observed. I like to reach under and dangle the berries. Two additional but often overlooked features I like are the variation in leaf shape and the occasional red pigmentation which is more pronounced in some cultivars. The aerial stems/stalks are also sometimes pigmented. The unearthed exhibited rhizomes in the bottom pic above are a cultivar of P. odoratum called 'Variegatum' also occasionally listed as var. thunbergii. While it tops out a bit shorter than many Solomon seals (at about two feet) I am not alone in favoring this cultivar -- it has been variously awarded.

If you live near Indianapolis, the best place to see and obtain Solomon's seal is Soules Garden. Chris and Cynthia have an excellent selection and are knowledgeable about its cultivation. You will find that Tony Avent's Plant Delights is one of the better online sources. He has some unusual kinds which are rarely available.